diff --git a/paddle/fluid/inference/analysis/CMakeLists.txt b/paddle/fluid/inference/analysis/CMakeLists.txt
index 47929ef7490e5edb246625cb0b3ba507039df27a..9faf5bb3036775a2ba0c08d3d6ea17ffa73753c6 100644
--- a/paddle/fluid/inference/analysis/CMakeLists.txt
+++ b/paddle/fluid/inference/analysis/CMakeLists.txt
@@ -1,2 +1,17 @@
-cc_library(analysis SRCS dot.cc node.cc node.h)
+set(FLUID_CORE_MODULES proto_desc memory lod_tensor executor init)
+cc_library(analysis SRCS dot.cc node.cc data_flow_graph.cc graph_traits.cc subgraph_splitter.cc fluid_to_data_flow_graph_pass.cc
+  DEPS paddle_fluid)
 cc_test(test_node SRCS node_tester.cc DEPS analysis)
+cc_test(test_dot SRCS dot_tester.cc DEPS analysis)
+
+set(PYTHON_TESTS_DIR ${PADDLE_BINARY_DIR}/python/paddle/fluid/tests)
+
+cc_test(test_data_flow_graph SRCS data_flow_graph_tester.cc DEPS analysis ${FLUID_CORE_MODULES} paddle_fluid
+  ARGS --inference_model_dir=${PYTHON_TESTS_DIR}/book/word2vec.inference.model)
+set_tests_properties(test_data_flow_graph PROPERTIES DEPENDS test_word2vec)
+
+cc_test(test_subgraph_splitter
+        SRCS subgraph_splitter_tester.cc
+        DEPS analysis paddle_fluid tensor
+        ARGS --inference_model_dir=${PYTHON_TESTS_DIR}/book/word2vec.inference.model)
+set_tests_properties(test_subgraph_splitter PROPERTIES DEPENDS test_word2vec)
diff --git a/paddle/fluid/inference/analysis/data_flow_graph.cc b/paddle/fluid/inference/analysis/data_flow_graph.cc
new file mode 100644
index 0000000000000000000000000000000000000000..4220451e3caee62caa51af5bc33d6dd3fd891018
--- /dev/null
+++ b/paddle/fluid/inference/analysis/data_flow_graph.cc
@@ -0,0 +1,205 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+#include "paddle/fluid/inference/analysis/data_flow_graph.h"
+#include "paddle/fluid/inference/analysis/dot.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+// It is a better idea that the inputs and outputs of this graph is set manully
+// before, but there must be a Pass that helps to prune the unnecessary ops that
+// do not contribute to the given targets, so in this pass, analysis and get the
+// inputs and outputs is OK.
+void DataFlowGraph::Build() {
+  inputs.clear();
+  outputs.clear();
+  std::unordered_set<Node *> ins;
+  std::unordered_set<Node *> outs;
+  for (auto &node : nodes.nodes()) {
+    for (auto *in : node->inlinks) {
+      ins.insert(in);
+    }
+    for (auto *out : node->outlinks) {
+      outs.insert(out);
+    }
+  }
+
+  // The nodes that in ins but not in outs is the graph's inputs
+  // similarly, the nodes that in outs but not in ins is the graphs' outputs
+  for (auto *in : ins) {
+    if (!outs.count(in)) {
+      inputs.push_back(in);
+    }
+  }
+  for (auto *out : outs) {
+    if (!outs.count(out)) {
+      outputs.push_back(out);
+    }
+  }
+}
+
+std::string DataFlowGraph::DotString() const {
+  Dot dot;
+
+  // Add nodes
+  for (size_t i = 0; i < nodes.size(); i++) {
+    const Node &node = nodes.Get(i);
+    switch (node.type()) {
+      case Node::Type::kValue:
+        dot.AddNode(node.repr(), node.dot_attrs());
+        break;
+      case Node::Type::kFunction:
+        dot.AddNode(node.repr(), node.dot_attrs());
+        break;
+      case Node::Type::kFunctionBlock:
+        dot.AddNode(node.repr(), node.dot_attrs());
+        break;
+      default:
+        PADDLE_THROW("unsupported Node type %d", static_cast<int>(node.type()));
+    }
+  }
+
+  // Add edges
+  for (size_t i = 0; i < nodes.size(); i++) {
+    const Node &node = nodes.Get(i);
+    for (auto &in : node.inlinks) {
+      dot.AddEdge(in->repr(), node.repr(), {});
+    }
+  }
+  return dot.Build();
+}
+
+//
+// NodesBFSIterator
+//
+
+GraphTraits<DataFlowGraph>::NodesBFSIterator::NodesBFSIterator(
+    const std::vector<Node *> &source)
+    : queue_(source.begin(), source.end()) {}
+
+// GraphTraits<DataFlowGraph>::NodesBFSIterator::NodesBFSIterator(
+//     GraphTraits<DataFlowGraph>::NodesBFSIterator &&other) noexcept
+//     : queue_(std::move(other.queue_)),
+//       visited_(std::move(other.visited_)) {}
+
+GraphTraits<DataFlowGraph>::NodesBFSIterator::NodesBFSIterator(
+    const GraphTraits<DataFlowGraph>::NodesBFSIterator &other)
+    : queue_(other.queue_), visited_(other.visited_) {}
+
+Node &GraphTraits<DataFlowGraph>::NodesBFSIterator::operator*() {
+  PADDLE_ENFORCE(!queue_.empty());
+  return *queue_.front();
+}
+
+Node *GraphTraits<DataFlowGraph>::NodesBFSIterator::operator->() {
+  PADDLE_ENFORCE(!queue_.empty());
+  return queue_.front();
+}
+
+GraphTraits<DataFlowGraph>::NodesBFSIterator &
+GraphTraits<DataFlowGraph>::NodesBFSIterator::operator=(
+    const GraphTraits<DataFlowGraph>::NodesBFSIterator &other) {
+  queue_ = other.queue_;
+  visited_ = other.visited_;
+  return *this;
+}
+
+GraphTraits<DataFlowGraph>::NodesBFSIterator
+    &GraphTraits<DataFlowGraph>::NodesBFSIterator::operator++() {
+  PADDLE_ENFORCE(!queue_.empty());
+  auto *cur = queue_.front();
+  visited_.insert(cur);
+  queue_.pop_front();
+  for (auto *output : cur->outlinks) {
+    if (!visited_.count(output)) {
+      queue_.push_back(output);
+      visited_.insert(output);
+    }
+  }
+  return *this;
+}
+
+bool GraphTraits<DataFlowGraph>::NodesBFSIterator::operator==(
+    const GraphTraits<DataFlowGraph>::NodesBFSIterator &other) {
+  if (queue_.empty()) return other.queue_.empty();
+  if ((!queue_.empty()) && (!other.queue_.empty())) {
+    return queue_.front() == other.queue_.front() &&
+           visited_.size() == other.visited_.size();  // here need to check the
+                                                      // equality of queue and
+    // visited. Just a light but week implementation.
+  }
+  return false;
+}
+
+//
+// NodesDFSIterator
+//
+GraphTraits<DataFlowGraph>::NodesDFSIterator::NodesDFSIterator(
+    const std::vector<Node *> &source) {
+  for (auto *x : source) stack_.push(x);
+}
+
+// GraphTraits<DataFlowGraph>::NodesDFSIterator::NodesDFSIterator(
+//     GraphTraits<DataFlowGraph>::NodesDFSIterator &&other) noexcept
+//     : stack_(std::move(other.stack_)),
+//       visited_(std::move(other.visited_)) {}
+
+GraphTraits<DataFlowGraph>::NodesDFSIterator::NodesDFSIterator(
+    const GraphTraits<DataFlowGraph>::NodesDFSIterator &other)
+    : stack_(other.stack_), visited_(other.visited_) {}
+
+Node &GraphTraits<DataFlowGraph>::NodesDFSIterator::operator*() {
+  PADDLE_ENFORCE(!stack_.empty());
+  return *stack_.top();
+}
+
+GraphTraits<DataFlowGraph>::NodesDFSIterator
+    &GraphTraits<DataFlowGraph>::NodesDFSIterator::operator++() {
+  if (stack_.empty()) return *this;
+  visited_.insert(stack_.top());
+  auto *cur = stack_.top();
+  stack_.pop();
+  for (auto *x : cur->outlinks) {
+    if (!visited_.count(x)) {
+      stack_.push(x);
+      visited_.insert(x);
+    }
+  }
+  return *this;
+}
+bool GraphTraits<DataFlowGraph>::NodesDFSIterator::operator==(
+    const GraphTraits<DataFlowGraph>::NodesDFSIterator &other) {
+  if (stack_.empty()) return other.stack_.empty();
+  if ((!stack_.empty()) && (!other.stack_.empty())) {
+    return stack_.top() == other.stack_.top();
+  }
+  return false;
+}
+
+GraphTraits<DataFlowGraph>::NodesDFSIterator &
+GraphTraits<DataFlowGraph>::NodesDFSIterator::operator=(
+    const GraphTraits<DataFlowGraph>::NodesDFSIterator &other) {
+  stack_ = other.stack_;
+  visited_ = other.visited_;
+  return *this;
+}
+Node *GraphTraits<DataFlowGraph>::NodesDFSIterator::operator->() {
+  return stack_.top();
+}
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/data_flow_graph.h b/paddle/fluid/inference/analysis/data_flow_graph.h
new file mode 100644
index 0000000000000000000000000000000000000000..9f6ce40ede25248a4f779b379c132806a4ec06ba
--- /dev/null
+++ b/paddle/fluid/inference/analysis/data_flow_graph.h
@@ -0,0 +1,159 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+/*
+ * Data flow graph is an pass that build the basic graph. It contains a graph
+ * and the iterators that enable the iteration over the graph.
+ */
+
+#pragma once
+
+#include <deque>
+#include <stack>
+#include <unordered_set>
+
+#include "paddle/fluid/inference/analysis/graph_traits.h"
+#include "paddle/fluid/inference/analysis/node.h"
+#include "paddle/fluid/platform/enforce.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+/*
+ * DataFlowGraph - A container of Value and Function Nodes.
+ */
+struct DataFlowGraph {
+  NodeMap nodes;
+  std::vector<Node *> inputs;
+  std::vector<Node *> outputs;
+
+  // Extract inputs and outputs of the graph.
+  void Build();
+
+  // Output a DOT graph file for debug.
+  std::string DotString() const;
+};
+
+/*
+ * An graph trait help to traverse the graph using BFS.
+ * The BFS start from a graph's inputs, the graph should be fully-connected, so
+ * that the iterator can reach the end.
+ */
+template <>
+struct GraphTraits<DataFlowGraph> {
+  // BFS iterator on nodes.
+  struct NodesBFSIterator
+      : public std::iterator<std::forward_iterator_tag, Node *> {
+    NodesBFSIterator() = default;
+    explicit NodesBFSIterator(const std::vector<Node *> &source);
+    // NodesBFSIterator(NodesBFSIterator &&other) noexcept;
+    // NOTE Heavy to use.
+    NodesBFSIterator(const NodesBFSIterator &other);
+
+    Node &operator*();
+    NodesBFSIterator &operator++();
+    Node *operator->();
+    // TODO(Superjomn) current implementation just compare the first
+    // element, need to compare the graph and all the elements in the queue and
+    // set.
+    NodesBFSIterator &operator=(const NodesBFSIterator &other);
+    bool operator==(const NodesBFSIterator &other);
+    bool operator!=(const NodesBFSIterator &other) { return !(*this == other); }
+
+   private:
+    std::deque<Node *> queue_;
+    std::unordered_set<Node *> visited_;
+  };
+
+  // DFS iterator on nodes.
+  struct NodesDFSIterator
+      : public std::iterator<std::forward_iterator_tag, Node *> {
+    NodesDFSIterator() = default;
+    explicit NodesDFSIterator(const std::vector<Node *> &source);
+    // NodesDFSIterator(NodesDFSIterator &&other) noexcept;
+    NodesDFSIterator(const NodesDFSIterator &other);
+
+    Node &operator*();
+    NodesDFSIterator &operator++();
+    // TODO(Superjomn) current implementation just compare the first
+    // element, need to compare the graph and all the elements in the queue and
+    // set.
+    NodesDFSIterator &operator=(const NodesDFSIterator &other);
+    bool operator==(const NodesDFSIterator &other);
+    bool operator!=(const NodesDFSIterator &other) { return !(*this == other); }
+    Node *operator->();
+
+   private:
+    std::stack<Node *> stack_;
+    std::unordered_set<Node *> visited_;
+  };
+
+  explicit GraphTraits(DataFlowGraph *graph) : graph_(graph) {}
+
+  // default use BFS to visit the nodes.
+  iterator_range<NodesBFSIterator> nodes() {
+    return iterator_range<NodesBFSIterator>(nodes_bfs_begin(), nodes_bfs_end());
+  }
+  iterator_range<NodesBFSIterator> nodes_in_BFS() {
+    return iterator_range<NodesBFSIterator>(nodes_bfs_begin(), nodes_bfs_end());
+  }
+  iterator_range<NodesDFSIterator> nodes_in_DFS() {
+    return iterator_range<NodesDFSIterator>(nodes_dfs_begin(), nodes_dfs_end());
+  }
+
+ private:
+  NodesBFSIterator nodes_bfs_begin() {
+    return NodesBFSIterator(graph_->inputs);
+  }
+  NodesBFSIterator nodes_bfs_end() { return NodesBFSIterator(); }
+  NodesDFSIterator nodes_dfs_begin() {
+    return NodesDFSIterator(graph_->inputs);
+  }
+  NodesDFSIterator nodes_dfs_end() { return NodesDFSIterator(); }
+
+ private:
+  DataFlowGraph *graph_;
+};
+
+// Extract the inputs and outputs of a graph. The inputs and outputs of a
+// sub-graph is the inputs nodes and output nodes that doesn't inside the
+// sub-graph.
+std::pair<
+    std::vector<Node *>,
+    std::vector<
+        Node *>> static ExtractInputAndOutputOfSubGraph(std::vector<Node *>
+                                                            &graph) {
+  std::unordered_set<Node *> nodes(graph.begin(), graph.end());
+  std::unordered_set<Node *> inputs;
+  std::unordered_set<Node *> outputs;
+  for (auto &node : graph) {
+    for (auto *in : node->inlinks) {
+      if (!nodes.count(in) && in->type() == Node::Type::kValue) {
+        inputs.insert(in);
+      }
+    }
+    for (auto *out : node->outlinks) {
+      if (!nodes.count(out) && out->type() == Node::Type::kValue) {
+        outputs.insert(out);
+      }
+    }
+  }
+  return std::make_pair(std::vector<Node *>(inputs.begin(), inputs.end()),
+                        std::vector<Node *>(outputs.begin(), outputs.end()));
+}
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/data_flow_graph_tester.cc b/paddle/fluid/inference/analysis/data_flow_graph_tester.cc
new file mode 100644
index 0000000000000000000000000000000000000000..15eddca1c760a44afb986796b08e2b8533695d60
--- /dev/null
+++ b/paddle/fluid/inference/analysis/data_flow_graph_tester.cc
@@ -0,0 +1,62 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License. */
+
+#include "paddle/fluid/inference/analysis/data_flow_graph.h"
+#include "paddle/fluid/inference/analysis/ut_helper.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+TEST(DataFlowGraph, BFS) {
+  auto desc = LoadProgramDesc();
+  auto dfg = ProgramDescToDFG(desc);
+  dfg.Build();
+
+  for (auto* in : dfg.inputs) {
+    LOG(INFO) << "inputs: " << in->name() << " "
+              << static_cast<int>(in->type());
+  }
+  for (auto* out : dfg.outputs) {
+    LOG(INFO) << "outputs: " << out->name() << " "
+              << static_cast<int>(out->type());
+  }
+
+  GraphTraits<DataFlowGraph> trait(&dfg);
+  auto nodes = trait.nodes();
+  int count = 0;
+  for (auto it = nodes.begin(); it != nodes.end(); ++it) {
+    LOG(INFO) << "visiting " << it->name();
+    ++count;
+  }
+  ASSERT_EQ(count, dfg.nodes.size());
+}
+
+TEST(DataFlowGraph, DFS) {
+  auto desc = LoadProgramDesc();
+  auto dfg = ProgramDescToDFG(desc);
+  dfg.Build();
+  GraphTraits<DataFlowGraph> trait(&dfg);
+  auto nodes = trait.nodes_in_DFS();
+  int count = 0;
+  for (auto it = nodes.begin(); it != nodes.end(); ++it) {
+    LOG(INFO) << "visiting " << it->name();
+    ++count;
+  }
+  ASSERT_EQ(count, dfg.nodes.size());
+}
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/data_flow_graph_to_fluid_pass_tester.cc b/paddle/fluid/inference/analysis/data_flow_graph_to_fluid_pass_tester.cc
new file mode 100644
index 0000000000000000000000000000000000000000..60f159da9140516284449a0274906df004b23ac5
--- /dev/null
+++ b/paddle/fluid/inference/analysis/data_flow_graph_to_fluid_pass_tester.cc
@@ -0,0 +1,49 @@
+//   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/fluid/inference/analysis/data_flow_graph_to_fluid_pass.h"
+
+#include <glog/logging.h>
+#include <google/protobuf/text_format.h>
+#include <gtest/gtest.h>
+#include "paddle/fluid/framework/executor.h"
+#include "paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.h"
+#include "paddle/fluid/inference/analysis/ut_helper.h"
+#include "paddle/fluid/inference/io.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+TEST_F(DFG_Tester, Test) {
+  framework::proto::ProgramDesc new_desc;
+  DataFlowGraph graph;
+
+  FluidToDataFlowGraphPass pass0;
+  DataFlowGraphToFluidPass pass1;
+  pass0.Initialize(desc);
+  pass1.Initialize(&new_desc);
+
+  pass0.Run(&graph);
+  pass1.Run(&graph);
+
+  pass0.Finalize();
+  pass1.Finalize();
+
+  LOG(INFO) << graph.nodes.size();
+}
+
+}  // analysis
+}  // inference
+}  // paddle
diff --git a/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.cc b/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.cc
new file mode 100644
index 0000000000000000000000000000000000000000..52851a9acb7f90826d520cc944d04fe1c90a22e0
--- /dev/null
+++ b/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.cc
@@ -0,0 +1,83 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License. */
+
+#include "paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.h"
+#include <vector>
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+FluidToDataFlowGraphPass::FluidToDataFlowGraphPass() {}
+
+bool FluidToDataFlowGraphPass::Initialize() { return Pass::Initialize(); }
+
+bool FluidToDataFlowGraphPass::Initialize(
+    const framework::proto::ProgramDesc &desc) {
+  desc_ = &desc;
+  return true;
+}
+
+bool FluidToDataFlowGraphPass::Finalize() { return Pass::Finalize(); }
+
+void FluidToDataFlowGraphPass::Run(DataFlowGraph *graph) {
+  // insert vars
+  std::unordered_map<std::string, size_t> var2id;
+  auto &main_block = desc_->blocks(framework::kRootBlockIndex);
+  for (int i = 0; i < main_block.vars_size(); i++) {
+    const auto &var = main_block.vars(i);
+    auto *v = graph->nodes.Create(Node::Type::kValue);
+    v->SetName(var.name());
+    v->SetExtraInfo(const_cast<void *>(static_cast<const void *>(&var)));
+    var2id[var.name()] = v->id();
+  }
+  for (int i = 0; i < main_block.ops_size(); i++) {
+    const auto &op = main_block.ops(i);
+    auto *o = graph->nodes.Create(Node::Type::kFunction);
+    o->SetName(op.type());
+    static_cast<Function *>(o)->SetFuncType(op.type());
+    // Link to the original protobuf message's memory, make it easier to
+    // generate from a data flow graph to fluid ProgramDesc.
+    o->SetExtraInfo(const_cast<void *>(static_cast<const void *>(&op)));
+    // set inputs and outputs
+    // TODO(Superjomn) make sure the InputNames is the real variable name.
+    for (int j = 0; j < op.inputs_size(); j++) {
+      auto &in_var = op.inputs(j);
+      for (int k = 0; k < in_var.arguments_size(); k++) {
+        auto *in = graph->nodes.GetMutable(var2id.at(in_var.arguments(k)));
+        in->outlinks.push_back(o);
+        o->inlinks.push_back(in);
+      }
+    }
+    for (int j = 0; j < op.outputs_size(); j++) {
+      auto &out_var = op.outputs(j);
+      for (int k = 0; k < out_var.arguments_size(); k++) {
+        auto *out = graph->nodes.GetMutable(var2id[out_var.arguments(k)]);
+        out->inlinks.push_back(o);
+        o->outlinks.push_back(out);
+      }
+    }
+  }
+  // Analysis and extract the inputs and outputs of this graph.
+  graph->Build();
+}
+
+Pass *FluidToDataFlowGraphPass::CreatePrinterPass(
+    std::ostream &os, const std::string &banner) const {
+  return nullptr;
+}
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.h b/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.h
new file mode 100644
index 0000000000000000000000000000000000000000..cd0d4fabaafe844bcc5bb8bfc2586971197d9167
--- /dev/null
+++ b/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.h
@@ -0,0 +1,51 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License. */
+
+/*
+ * This file implements the transformation from data flow graph to fluid
+ * ProgramDesc.
+ */
+
+#pragma once
+
+#include "paddle/fluid/framework/program_desc.h"
+#include "paddle/fluid/inference/analysis/data_flow_graph.h"
+#include "paddle/fluid/inference/analysis/pass.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+/*
+ * Transform a FluidDesc to a data flow graph.
+ */
+class FluidToDataFlowGraphPass final : public DataFlowGraphPass {
+ public:
+  FluidToDataFlowGraphPass();
+  bool Initialize() override;
+  bool Initialize(const framework::proto::ProgramDesc &desc) override;
+  bool Finalize() override;
+
+  void Run(DataFlowGraph *graph) override;
+
+  Pass *CreatePrinterPass(std::ostream &os,
+                          const std::string &banner) const override;
+
+ private:
+  framework::proto::ProgramDesc const *desc_;
+};
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass_tester.cc b/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass_tester.cc
new file mode 100644
index 0000000000000000000000000000000000000000..851c98bef305fa9e20dced5f7c26e9d1b6ddf4f2
--- /dev/null
+++ b/paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass_tester.cc
@@ -0,0 +1,37 @@
+//   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.h"
+
+#include <gtest/gtest.h>
+#include "paddle/fluid/inference/analysis/ut_helper.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+TEST_F(DFG_Tester, Init) {
+  FluidToDataFlowGraphPass pass;
+  pass.Initialize();
+  pass.Initialize(desc);
+  DataFlowGraph graph;
+  pass.Run(&graph);
+  ASSERT_GT(graph.nodes.size(), 0);
+  pass.Finalize();
+  LOG(INFO) << '\n' << graph.DotString();
+}
+
+}  // analysis
+}  // inference
+}  // paddle
diff --git a/paddle/fluid/inference/analysis/graph_traits.cc b/paddle/fluid/inference/analysis/graph_traits.cc
new file mode 100644
index 0000000000000000000000000000000000000000..272dbb799f3759a3f6e34e93bc115cf2cea6ec3b
--- /dev/null
+++ b/paddle/fluid/inference/analysis/graph_traits.cc
@@ -0,0 +1,15 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License. */
+
+#include "paddle/fluid/inference/analysis/graph_traits.h"
diff --git a/paddle/fluid/inference/analysis/graph_traits.h b/paddle/fluid/inference/analysis/graph_traits.h
new file mode 100644
index 0000000000000000000000000000000000000000..aed2b1e8e27d94b430201d70ecf09d4acc33c8fa
--- /dev/null
+++ b/paddle/fluid/inference/analysis/graph_traits.h
@@ -0,0 +1,63 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+/*
+ * This file defines the GraphTraits<X> template class that should be specified
+ * by classes that want to be iteratable by generic graph iterators.
+ *
+ * This file also defines the marker class Inverse that is used to iterate over
+ * graphs in a graph defined, inverse ordering...
+ */
+
+#pragma once
+
+#include "paddle/fluid/inference/analysis/helper.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+/*
+ * This class should be specialized by different graph types...
+ * That's why the base class is empty.
+ */
+template <typename GraphType>
+struct GraphTraits {
+  // using NodesBFSIterator = xxx
+
+  // NodesBFSIterator nodes_begin();
+  // NodesBFSIterator nodes_end();
+};
+
+/*
+ * Inverse - This class is used as a marker class to tell the graph iterator to
+ * iterate in a graph defined Inverse order.
+ */
+template <typename GraphType>
+struct Inverse {
+  const GraphType &graph;
+
+  explicit Inverse(const GraphType &graph) : graph(graph) {}
+};
+
+/*
+ * Provide a partial specialization of GraphTraits so that the inverse of an
+ * inverse turns into the original graph.
+ */
+template <typename GraphType>
+struct GraphTraits<Inverse<Inverse<GraphType>>> : GraphTraits<GraphType> {};
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/helper.h b/paddle/fluid/inference/analysis/helper.h
index b2d06c5d63ff139186710cd963e07b4ba245f9f3..a79e9cbda105f3bcaf100b3f6ea2c2634e0e2451 100644
--- a/paddle/fluid/inference/analysis/helper.h
+++ b/paddle/fluid/inference/analysis/helper.h
@@ -1,74 +1,107 @@
-/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
-
- Licensed under the Apache License, Version 2.0 (the "License");
- you may not use this file except in compliance with the License.
- You may obtain a copy of the License at
-
- http://www.apache.org/licenses/LICENSE-2.0
-
- Unless required by applicable law or agreed to in writing, software
- distributed under the License is distributed on an "AS IS" BASIS,
- WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
- See the License for the specific language governing permissions and
- limitations under the License. */
-
-#pragma once
-
-#include <string>
-#include <unordered_map>
-#include <vector>
-
-#include "paddle/fluid/platform/enforce.h"
-
-namespace paddle {
-namespace inference {
-namespace analysis {
-
-template <typename IteratorT>
-class iterator_range {
-  IteratorT begin_, end_;
-
- public:
-  template <typename Container>
-  explicit iterator_range(Container &&c) : begin_(c.begin()), end_(c.end()) {}
-
-  iterator_range(const IteratorT &begin, const IteratorT &end)
-      : begin_(begin), end_(end) {}
-
-  const IteratorT &begin() const { return begin_; }
-  const IteratorT &end() const { return end_; }
-};
-
-/*
- * An registry helper class, with its records keeps the order they registers.
- */
-template <typename T>
-class OrderedRegistry {
- public:
-  T *Register(const std::string &name, T *x) {
-    PADDLE_ENFORCE(!dic_.count(name));
-    dic_[name] = data_.size();
-    data_.emplace_back(std::unique_ptr<T>(x));
-    return data_.back().get();
-  }
-
-  T *Lookup(const std::string &name) {
-    auto it = dic_.find(name);
-    if (it == dic_.end()) return nullptr;
-    return data_[it->second].get();
-  }
-
- protected:
-  std::unordered_map<std::string, int> dic_;
-  std::vector<std::unique_ptr<T>> data_;
-};
-
-}  // namespace analysis
-}  // namespace inference
-}  // namespace paddle
-
-#define PADDLE_DISALLOW_COPY_AND_ASSIGN(type__) \
-                                                \
-  type__(const type__ &) = delete;              \
-                                                \
-  void operator=(const type__ &) = delete;
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+ Licensed under the Apache License, Version 2.0 (the "License");
+ you may not use this file except in compliance with the License.
+ You may obtain a copy of the License at
+
+ http://www.apache.org/licenses/LICENSE-2.0
+
+ Unless required by applicable law or agreed to in writing, software
+ distributed under the License is distributed on an "AS IS" BASIS,
+ WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ See the License for the specific language governing permissions and
+ limitations under the License. */
+
+#pragma once
+
+#include <string>
+#include <unordered_map>
+#include <vector>
+
+#include "paddle/fluid/platform/enforce.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+#define SET_TYPE(type__) dic_[typeid(type__).hash_code()] = #type__;
+/*
+ * Map typeid to representation.
+ */
+struct DataTypeNamer {
+  static const DataTypeNamer &Global() {
+    static auto *x = new DataTypeNamer();
+    return *x;
+  }
+
+  template <typename T>
+  const std::string &repr() const {
+    auto x = typeid(T).hash_code();
+    PADDLE_ENFORCE(dic_.count(x), "unknown type for representation");
+    return dic_.at(x);
+  }
+
+  const std::string &repr(size_t &hash) const {
+    PADDLE_ENFORCE(dic_.count(hash), "unknown type for representation");
+    return dic_.at(hash);
+  }
+
+ private:
+  DataTypeNamer() {
+    SET_TYPE(int);
+    SET_TYPE(bool);
+    SET_TYPE(float);
+  }
+
+  std::unordered_map<decltype(typeid(int).hash_code()), std::string> dic_;
+};
+#undef SET_TYPE
+
+template <typename IteratorT>
+class iterator_range {
+  IteratorT begin_, end_;
+
+ public:
+  template <typename Container>
+  explicit iterator_range(Container &&c) : begin_(c.begin()), end_(c.end()) {}
+
+  iterator_range(const IteratorT &begin, const IteratorT &end)
+      : begin_(begin), end_(end) {}
+
+  const IteratorT &begin() const { return begin_; }
+  const IteratorT &end() const { return end_; }
+};
+
+/*
+ * An registry helper class, with its records keeps the order they registers.
+ */
+template <typename T>
+class OrderedRegistry {
+ public:
+  T *Register(const std::string &name, T *x) {
+    PADDLE_ENFORCE(!dic_.count(name));
+    dic_[name] = data_.size();
+    data_.emplace_back(std::unique_ptr<T>(x));
+    return data_.back().get();
+  }
+
+  T *Lookup(const std::string &name) {
+    auto it = dic_.find(name);
+    if (it == dic_.end()) return nullptr;
+    return data_[it->second].get();
+  }
+
+ protected:
+  std::unordered_map<std::string, int> dic_;
+  std::vector<std::unique_ptr<T>> data_;
+};
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
+
+#define PADDLE_DISALLOW_COPY_AND_ASSIGN(type__) \
+                                                \
+  type__(const type__ &) = delete;              \
+                                                \
+  void operator=(const type__ &) = delete;
diff --git a/paddle/fluid/inference/analysis/node.h b/paddle/fluid/inference/analysis/node.h
index 07cb7669f98237399c4165947a03c67ce2a86aa8..7972ca25c92186a8c55a76de645f4fdbb089e8d3 100644
--- a/paddle/fluid/inference/analysis/node.h
+++ b/paddle/fluid/inference/analysis/node.h
@@ -117,7 +117,10 @@ class Node {
         type_hash_ = typeid(T).hash_code();
         data_.resize(sizeof(T));
       }
-      PADDLE_ENFORCE(type_hash_ == typeid(T).hash_code(), "type not matched");
+      PADDLE_ENFORCE(type_hash_ == typeid(T).hash_code(),
+                     "type not matched, origin is %s, want %s",
+                     DataTypeNamer::Global().repr(type_hash_),
+                     DataTypeNamer::Global().repr<T>());
       PADDLE_ENFORCE_EQ(data_.size(), sizeof(T), "Node attr type recast error");
       return *reinterpret_cast<T *>(&data_[0]);
     }
@@ -127,6 +130,10 @@ class Node {
     size_t type_hash_{std::numeric_limits<size_t>::max()};
   };
 
+  bool IsFunction() const { return type_ == Node::Type::kFunction; }
+  bool IsValue() const { return type_ == Node::Type::kValue; }
+  bool IsFunctionBlock() const { return type_ == Node::Type::kFunctionBlock; }
+
   virtual ~Node() {}
 
   friend class NodeMap;
diff --git a/paddle/fluid/inference/analysis/pass.cc b/paddle/fluid/inference/analysis/pass.cc
new file mode 100644
index 0000000000000000000000000000000000000000..b48a4fd83497a068392fd941028fef542e45d763
--- /dev/null
+++ b/paddle/fluid/inference/analysis/pass.cc
@@ -0,0 +1,15 @@
+//   Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "paddle/fluid/inference/analysis/pass.h"
\ No newline at end of file
diff --git a/paddle/fluid/inference/analysis/pass.h b/paddle/fluid/inference/analysis/pass.h
new file mode 100644
index 0000000000000000000000000000000000000000..5c89b1304d84abc9a4942f12da46b4bfe76f44f5
--- /dev/null
+++ b/paddle/fluid/inference/analysis/pass.h
@@ -0,0 +1,90 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+#pragma once
+
+#include <glog/logging.h>
+#include <iosfwd>
+
+#include "paddle/fluid/framework/framework.pb.h"
+#include "paddle/fluid/inference/analysis/data_flow_graph.h"
+#include "paddle/fluid/inference/analysis/helper.h"
+#include "paddle/fluid/inference/analysis/node.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+class Pass {
+ public:
+  Pass() = default;
+  virtual ~Pass() {}
+  // Virtual method overridden by subclasses to do only necessary initialization
+  // before any pass is run.
+  virtual bool Initialize() { return false; }
+  // There is some passes such as FlowToDataFlowGraphPass that needs a
+  // ProgramDesc. Here use the native ProgramDesc ProtoBuf message, so that it
+  // only couple with the proto file.
+  virtual bool Initialize(const framework::proto::ProgramDesc &desc) {
+    return false;
+  }
+  // There are some Passes such as DataFlowGraphToFluidPass that will output a
+  // ProgramDesc.
+  virtual bool Initialize(framework::proto::ProgramDesc *desc) { return false; }
+
+  // Virtual method overriden by subclasses to do any necessary clean up after
+  // all passes have run.
+  virtual bool Finalize() { return false; }
+
+  // Get a Pass appropriate to print the Node this pass operates on.
+  virtual Pass *CreatePrinterPass(std::ostream &os,
+                                  const std::string &banner) const = 0;
+
+  // Run on a single Node.
+  virtual void Run(Node *x) { LOG(FATAL) << "not valid"; }
+  // Run on a single Function.
+  virtual void Run(Function *x) { LOG(FATAL) << "not valid"; }
+  // Run on a single FunctionBlock.
+  virtual void Run(FunctionBlock *x) { LOG(FATAL) << "not valid"; }
+  // Run on a single DataFlowGraph.
+  virtual void Run(DataFlowGraph *x) { LOG(FATAL) << "not valid"; }
+};
+
+// NodePass process on any Node types.
+class NodePass : public Pass {
+ public:
+  virtual void Run(Node *node) = 0;
+};
+
+// NodePass process on any Function node types.
+class FunctionPass : public Pass {
+ public:
+  virtual void Run(Function *node) = 0;
+};
+
+// NodePass process on any FunctionBlock node types.
+class FunctionBlockPass : public Pass {
+ public:
+  virtual void Run(FunctionBlock *node) = 0;
+};
+
+// GraphPass processes on any GraphType.
+class DataFlowGraphPass : public Pass {
+ public:
+  virtual void Run(DataFlowGraph *graph) = 0;
+};
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/subgraph_splitter.cc b/paddle/fluid/inference/analysis/subgraph_splitter.cc
new file mode 100644
index 0000000000000000000000000000000000000000..43ccac96c84e987ad1f494af3e314c810fc1ffe3
--- /dev/null
+++ b/paddle/fluid/inference/analysis/subgraph_splitter.cc
@@ -0,0 +1,154 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+#include "paddle/fluid/inference/analysis/subgraph_splitter.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+const char *SubGraphSplitter::kMarkerAttrName =
+    "_sub_graph_splitter_inside_sub_graph";
+
+std::vector<std::vector<Node *>> SubGraphSplitter::operator()() {
+  MarkNodesInsideSubGraph();
+  return ExtractSubGraphs();
+}
+
+// Mark the output variables inside a subgraph with the func.
+inline void MarkOutLinksInSubGraph(const Function *func) {
+  for (auto *var : func->outlinks) {
+    var->attr(SubGraphSplitter::kMarkerAttrName).Bool() = true;
+  }
+}
+
+void SubGraphSplitter::MarkNodesInsideSubGraph() {
+  for (auto &node : GraphTraits<DataFlowGraph>(graph_).nodes()) {
+    if (node_inside_subgraph_teller_(&node)) {
+      node.attr(kMarkerAttrName).Bool() = true;
+      if (node.type() == Node::Type::kFunction) {
+        // If a function is inside the sub-graph, mark all the output variables
+        // to be inside too, so that two marked functions will be inside a same
+        // sub-graph, lets take a example:  A_function->var->B_function, if
+        // A_function is marked, var should also be marked, so that B_function
+        // will be in the same sub-graph with A_function if B_function is
+        // marked.
+        MarkOutLinksInSubGraph(static_cast<const Function *>(&node));
+      }
+    }
+  }
+}
+
+const char *kUnionFindParent = "_sub_graph_splitter_union_find_parent_";
+
+// Use the Union Find(UF) algorithm to find fully connected sub-graphs, if node
+// a's output is node b, that is a and b is in the same sub-graph. The UF
+// algorithm will group them to the same cluster.
+using node_map_t = std::unordered_map<int, Node *>;
+// Find the ancestor id of a node.
+int UnionFindGetAncestor(const node_map_t &node_map, size_t id) {
+  int tmp = id;
+  do {
+    tmp = node_map.at(tmp)->attr(kUnionFindParent).Int32();
+  } while (node_map.at(tmp)->attr(kUnionFindParent).Int32() != tmp);
+  return tmp;
+}
+// Make this two node share the same ancestor.
+// TODO(Superjom) bad performance, make a balanced tree latter.
+void UnionFindCombine(const node_map_t &node_map, size_t a, size_t b) {
+  int a_ancestor = UnionFindGetAncestor(node_map, a);
+  int b_ancestor = UnionFindGetAncestor(node_map, b);
+  node_map.at(b_ancestor)->attr(kUnionFindParent).Int32() = a_ancestor;
+  node_map.at(a)->attr(kUnionFindParent).Int32() = a_ancestor;
+  node_map.at(b)->attr(kUnionFindParent).Int32() = a_ancestor;
+}
+
+std::vector<std::vector<Node *>> SubGraphSplitter::ExtractSubGraphs() {
+  std::vector<Node *> marked_nodes;
+  for (auto &node : GraphTraits<DataFlowGraph>(graph_).nodes()) {
+    if (node.attr(kMarkerAttrName).Bool()) {
+      marked_nodes.push_back(&node);
+    }
+  }
+  // extract sub-graphs in the marked node set, use Union Find algorithm.
+  node_map_t node_map;  // id to ptr
+  for (auto *n : marked_nodes) {
+    // n's parent == n.id means it is the ancestor
+    n->attr(kUnionFindParent).Int32() = n->id();
+    node_map[n->id()] = n;
+  }
+  std::unordered_set<Node *> visited;
+  for (auto *n : marked_nodes) {
+    for (auto *out : n->outlinks) {
+      if (node_map.count(out->id())) {
+        UnionFindCombine(node_map, n->id(), out->id());
+      }
+    }
+  }
+
+  std::unordered_map<int /*ancestor*/, std::vector<Node *>> clusters;
+  for (auto *n : marked_nodes) {
+    if (n->type() == Node::Type::kFunction) {
+      clusters[UnionFindGetAncestor(node_map,
+                                    n->attr(kUnionFindParent).Int32())]
+          .push_back(n);
+    }
+  }
+  std::vector<std::vector<Node *>> result;
+  std::for_each(clusters.begin(), clusters.end(),
+                [&](const decltype(clusters)::value_type &it) {
+                  result.push_back(it.second);
+                });
+
+  return result;
+}
+
+void SubGraphFuse::operator()() { ReplaceNodesWithSubGraphs(); }
+
+void SubGraphFuse::ReplaceNodesWithSubGraphs() {
+  auto subgraphs = SubGraphSplitter(graph_, node_inside_subgraph_teller_)();
+  for (auto &subgraph : subgraphs) {
+    // replace this sub-graph with the first node. Two steps: 1. Create a Block
+    // Node that contains this subgraph 2. Mark the nodes inside the sub-graph
+    // as deleted. 3. Replace the deleted node with the new Block Node.
+    auto *block_node = graph_->nodes.Create(Node::Type::kFunctionBlock);
+    auto io = ExtractInputAndOutputOfSubGraph(subgraph);
+    block_node->inlinks = std::move(io.first);
+    block_node->outlinks = std::move(io.second);
+    for (auto *node : subgraph) {
+      // TODO(Superjomn) need a unified mechanism to treat deleted node in each
+      // pass.
+      node->SetDeleted();
+    }
+
+    std::unordered_map<Node *, Node *>
+        delelte_node_map;  // deleted node to BlockNode
+    for (auto *n : block_node->inlinks) {
+      n->inlinks.clear();
+    }
+    for (auto *n : block_node->outlinks) {
+      n->outlinks.clear();
+    }
+    for (auto *n : block_node->inlinks) {
+      n->outlinks.push_back(block_node);
+    }
+    for (auto *n : block_node->outlinks) {
+      n->inlinks.push_back(n);
+    }
+  }
+}
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/subgraph_splitter.h b/paddle/fluid/inference/analysis/subgraph_splitter.h
new file mode 100644
index 0000000000000000000000000000000000000000..ed90a0dcf31e154c4d82be08ce35e2f11d11c139
--- /dev/null
+++ b/paddle/fluid/inference/analysis/subgraph_splitter.h
@@ -0,0 +1,81 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+Licensed under the Apache License, Version 2.0 (the "License");
+you may not use this file except in compliance with the License.
+You may obtain a copy of the License at
+
+http://www.apache.org/licenses/LICENSE-2.0
+
+Unless required by applicable law or agreed to in writing, software
+distributed under the License is distributed on an "AS IS" BASIS,
+WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+See the License for the specific language governing permissions and
+limitations under the License. */
+
+/*
+ * This file defines the the class to partition a graph.
+ */
+
+#pragma once
+
+#include "paddle/fluid/inference/analysis/data_flow_graph.h"
+#include "paddle/fluid/inference/analysis/node.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+/*
+ * Detect the nodes in a sub-graph that meet some conditions. This class doesn't
+ * modify the graph.
+ */
+class SubGraphSplitter {
+ public:
+  static const char *kMarkerAttrName;
+  // Tell whether a node is inside a sub-graph.
+  using NodeInsideSubgraphTeller = std::function<bool(const Node *)>;
+
+  SubGraphSplitter(DataFlowGraph *graph, const NodeInsideSubgraphTeller &teller)
+      : graph_(graph), node_inside_subgraph_teller_(teller) {}
+
+  std::vector<std::vector<Node *>> operator()();
+
+ protected:
+  // Mark the nodes inside the accepted sub-graph using
+  // node_inside_subgraph_teller.
+  void MarkNodesInsideSubGraph();
+
+  // Merge the marked nodes into sub-graphs and return the sub-graphs.
+  std::vector<std::vector<Node *>> ExtractSubGraphs();
+
+ private:
+  DataFlowGraph *graph_;
+  NodeInsideSubgraphTeller node_inside_subgraph_teller_;
+};
+
+/*
+ * SubGraphFuse - Replace some nodes with the sub-graph node they are inside. To
+ * some extent, the TensorRT engine is just a fusion op for a model.
+ */
+class SubGraphFuse {
+ public:
+  using NodeInsideSubgraphTeller = SubGraphSplitter::NodeInsideSubgraphTeller;
+
+  SubGraphFuse(DataFlowGraph *graph, const NodeInsideSubgraphTeller &teller)
+      : graph_(graph), node_inside_subgraph_teller_(teller) {}
+
+  // The main method which run all the logic.
+  void operator()();
+
+ protected:
+  // Remove the nodes inside sub-graphs and replace with the SubGraphNode.
+  void ReplaceNodesWithSubGraphs();
+
+ private:
+  DataFlowGraph *graph_;
+  NodeInsideSubgraphTeller node_inside_subgraph_teller_;
+};
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/subgraph_splitter_tester.cc b/paddle/fluid/inference/analysis/subgraph_splitter_tester.cc
new file mode 100644
index 0000000000000000000000000000000000000000..6f695965afc9b462963660cabf988bfd81f0ba5c
--- /dev/null
+++ b/paddle/fluid/inference/analysis/subgraph_splitter_tester.cc
@@ -0,0 +1,67 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License. */
+
+#include "paddle/fluid/inference/analysis/subgraph_splitter.h"
+#include "paddle/fluid/inference/analysis/ut_helper.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+TEST_F(DFG_Tester, Split) {
+  auto desc = LoadProgramDesc();
+  auto dfg = ProgramDescToDFG(desc);
+  LOG(INFO) << "spliter\n" << dfg.DotString();
+
+  SubGraphSplitter::NodeInsideSubgraphTeller teller = [](const Node* node) {
+    if (node->type() != Node::Type::kFunction) return false;
+    const auto* func = static_cast<const Function*>(node);
+    if (func->func_type() == "elementwise_add" || func->func_type() == "relu" ||
+        func->func_type() == "conv2d" || func->func_type() == "mul" ||
+        func->func_type() == "sigmoid" || func->func_type() == "softmax") {
+      LOG(INFO) << "sub-graph marked " << node->repr();
+      return true;
+    }
+    return false;
+  };
+  ASSERT_GT(dfg.nodes.size(), 5UL);
+
+  auto subgraphs = SubGraphSplitter(&dfg, teller)();
+
+  // Check the number of the marked nodes.
+  int marked_nodes = 0;
+  for (auto& node : dfg.nodes.nodes()) {
+    if (node->IsFunction() &&
+        node->attr(SubGraphSplitter::kMarkerAttrName).Bool()) {
+      ++marked_nodes;
+    }
+  }
+  EXPECT_EQ(marked_nodes, 6);
+
+  // For human debug.
+  for (auto& subgraph : subgraphs) {
+    LOG(INFO) << "subgraph size " << subgraph.size();
+    for (auto* node : subgraph) {
+      LOG(INFO) << "node " << node->repr();
+    }
+  }
+
+  ASSERT_EQ(subgraphs.size(), 1UL);
+  // The last sub-graph has 5 Functions.
+  ASSERT_EQ(subgraphs.back().size(), 6UL);
+}
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle
diff --git a/paddle/fluid/inference/analysis/ut_helper.h b/paddle/fluid/inference/analysis/ut_helper.h
new file mode 100644
index 0000000000000000000000000000000000000000..f63550dba3549ad300ab54f5eab63770848f9833
--- /dev/null
+++ b/paddle/fluid/inference/analysis/ut_helper.h
@@ -0,0 +1,59 @@
+/* Copyright (c) 2018 PaddlePaddle Authors. All Rights Reserved.
+
+   Licensed under the Apache License, Version 2.0 (the "License");
+   you may not use this file except in compliance with the License.
+   You may obtain a copy of the License at
+
+   http://www.apache.org/licenses/LICENSE-2.0
+
+   Unless required by applicable law or agreed to in writing, software
+   distributed under the License is distributed on an "AS IS" BASIS,
+   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+   See the License for the specific language governing permissions and
+   limitations under the License. */
+
+#pragma once
+#include <gflags/gflags.h>
+#include <gtest/gtest.h>
+#include "paddle/fluid/framework/executor.h"
+#include "paddle/fluid/inference/analysis/data_flow_graph.h"
+#include "paddle/fluid/inference/analysis/fluid_to_data_flow_graph_pass.h"
+#include "paddle/fluid/inference/analysis/ut_helper.h"
+#include "paddle/fluid/inference/io.h"
+
+namespace paddle {
+namespace inference {
+namespace analysis {
+
+DEFINE_string(inference_model_dir, "", "inference test model dir");
+
+static framework::proto::ProgramDesc LoadProgramDesc(
+    const std::string& model_dir = FLAGS_inference_model_dir) {
+  // TODO(Superjomn) update latter.
+  auto place = paddle::platform::CPUPlace();
+  auto executor = paddle::framework::Executor(place);
+  auto* scope = new paddle::framework::Scope();
+  auto program = Load(&executor, scope, model_dir);
+  return *program->Proto();
+}
+
+static DataFlowGraph ProgramDescToDFG(
+    const framework::proto::ProgramDesc& desc) {
+  DataFlowGraph graph;
+  FluidToDataFlowGraphPass pass;
+  pass.Initialize(desc);
+  pass.Run(&graph);
+  pass.Finalize();
+  return graph;
+}
+
+class DFG_Tester : public ::testing::Test {
+ protected:
+  void SetUp() override { desc = LoadProgramDesc(FLAGS_inference_model_dir); }
+
+  framework::proto::ProgramDesc desc;
+};
+
+}  // namespace analysis
+}  // namespace inference
+}  // namespace paddle