diff --git a/oneflow/blob/blob_descriptor.h b/oneflow/blob/blob_descriptor.h
index 2ca91830f472aa3e1b43293e0ab3ae78df02378a..e6e5011a7f72afb487f6b83c582961f25a52e125 100644
--- a/oneflow/blob/blob_descriptor.h
+++ b/oneflow/blob/blob_descriptor.h
@@ -26,7 +26,6 @@ class BlobDescriptor {
   Shape& mutable_shape() { return shape_; }
   MemoryContext& mutable_memory_context() { return memory_context_; }
   FloatType& mutable_float_type() { return float_type_; }
-  
  
  private:
   Shape shape_;
diff --git a/oneflow/common/proto_io.cpp b/oneflow/common/proto_io.cpp
index ab1b781468bdf73cf9058dea824b31605bb94c94..ac9e400789d9a3dfde8fa12bbc912823220cee80 100644
--- a/oneflow/common/proto_io.cpp
+++ b/oneflow/common/proto_io.cpp
@@ -18,6 +18,9 @@ using google::protobuf::io::ZeroCopyInputStream;
 using google::protobuf::io::CodedInputStream;
 using google::protobuf::io::ZeroCopyOutputStream;
 using google::protobuf::io::CodedOutputStream;
+using google::protobuf::Descriptor;
+using google::protobuf::Reflection;
+using google::protobuf::FieldDescriptor;
 
 // string
 void ParseProtoFromString(const std::string& str, PbMessage* proto) {
@@ -43,4 +46,13 @@ void PrintProtoToTextFile(const PbMessage& proto,
   close(fd);
 }
 
+std::string GetStringValueFromPbMessage(const PbMessage& msg,
+                                        const std::string& key) {
+  const Descriptor* d = msg.GetDescriptor();
+  const FieldDescriptor* fd = d->FindFieldByName(key);
+  CHECK_NOTNULL(fd);
+  const Reflection* r = msg.GetReflection();
+  return r->GetString(msg, fd);
+}
+
 } // namespace oneflow
diff --git a/oneflow/common/proto_io.h b/oneflow/common/proto_io.h
index 0a5e1d6333eca64e505366bc1e66e7032a923294..328d5445a48b7aa4dd56acd01559b6545b5c6e55 100644
--- a/oneflow/common/proto_io.h
+++ b/oneflow/common/proto_io.h
@@ -19,6 +19,9 @@ void ParseProtoFromTextFile(const std::string& file_path,
 void PrintProtoToTextFile(const PbMessage& proto,
                           const std::string& file_path);
 
+std::string GetStringValueFromPbMessage(const PbMessage& msg,
+                                        const std::string& key);
+
 } // namespace caffe
 
 #endif // ONEFLOW_PROTO_IO_H_
diff --git a/oneflow/dag/dag.cpp b/oneflow/dag/dag.cpp
index f0bc5835a6ebfc8a004aae64d3be0c7c42e6a036..34fcf1faa096b942bc0c41b8b289d1b86df51a95 100644
--- a/oneflow/dag/dag.cpp
+++ b/oneflow/dag/dag.cpp
@@ -42,4 +42,15 @@ bool Dag::DagIterator::operator != (const Dag::DagIterator& rhs) const {
   }
 }
 
+void Dag::ConnectStartAndStop() {
+  for (DagNode* node : data_op_node_vec_) {
+    if (node->predecessors().empty()) {
+      node->AddPredecessor(&start_node_);
+    }
+    if (node->successors().empty()) {
+      stop_node_.AddPredecessor(node);
+    }
+  }
+}
+
 } // namespace oneflow
diff --git a/oneflow/dag/dag.h b/oneflow/dag/dag.h
index acf2c39a90a39419e62b9ca1566d4976dbc435a7..8cd264de77f9ae86c8aacb660298353c14305bff 100644
--- a/oneflow/dag/dag.h
+++ b/oneflow/dag/dag.h
@@ -92,11 +92,33 @@ class Dag {
     return ret;
   }
 
+ protected:
+  void ConnectStartAndStop();
+
+  void RegisterDataNode(std::unique_ptr<DataNode> new_node) {
+    data_op_node_vec_.push_back(new_node.get());
+    data_node_vec_.push_back(std::move(new_node));
+  }
+  void RegisterOpNode(std::unique_ptr<OpNode> new_node) {
+    data_op_node_vec_.push_back(new_node.get());
+    op_node_vec_.push_back(std::move(new_node));
+  }
+
+  const std::vector<std::unique_ptr<OpNode>>& op_node_vec() const {
+    return op_node_vec_;
+  }
+
  private:
   std::string dag_name_;
   DagNode start_node_;
   DagNode stop_node_;
 
+  // In future we can implement a Iterator to replace the data_op_node_vec_
+  // which is redundancy
+  std::vector<DagNode*> data_op_node_vec_; 
+  std::vector<std::unique_ptr<DataNode>> data_node_vec_;
+  std::vector<std::unique_ptr<OpNode>> op_node_vec_;
+
 };
 
 } // namespace oneflow
diff --git a/oneflow/dag/dag_node.h b/oneflow/dag/dag_node.h
index 206a8072c0cd526ce72b3c94ea0b13387ad1abf1..be3e4d2534435c09428031785f0c6355c9cfced1 100644
--- a/oneflow/dag/dag_node.h
+++ b/oneflow/dag/dag_node.h
@@ -39,5 +39,36 @@ class DagNode {
 
 };
 
+class DataNode : public DagNode {
+ public:
+  DISALLOW_COPY_AND_MOVE(DataNode);
+  virtual ~DataNode() = default;
+ 
+ protected:
+  DataNode() = default;
+  void Init() {
+    DagNode::Init();
+  }
+
+ private:
+
+};
+
+class OpNode : public DagNode {
+ public:
+  DISALLOW_COPY_AND_MOVE(OpNode);
+
+  virtual ~OpNode() = default;
+
+ protected:
+  OpNode() = default;
+  void Init() {
+    DagNode::Init();
+  }
+ 
+ private:
+
+};
+
 } // namespace oneflow
 #endif  // ONEFLOW_DAG_DAG_NODE_H_
diff --git a/oneflow/dag/dag_node_test.cpp b/oneflow/dag/dag_node_test.cpp
index 0d97b197443c4269f1a0c2f28808313503463040..eb82f9d6d43994bde3fc821b11ee32e1fdcd249f 100644
--- a/oneflow/dag/dag_node_test.cpp
+++ b/oneflow/dag/dag_node_test.cpp
@@ -2,8 +2,7 @@
 #include <vector>
 #include "gtest/gtest.h"
 #include "common/util.h"
-#include "dag/data_node.h"
-#include "dag/op_node.h"
+#include "dag/dag_node.h"
 
 namespace oneflow {
 
diff --git a/oneflow/dag/data_node.h b/oneflow/dag/data_node.h
deleted file mode 100644
index ba75a80ef1f711b7cf5edebb514ed02353f0d4d1..0000000000000000000000000000000000000000
--- a/oneflow/dag/data_node.h
+++ /dev/null
@@ -1,25 +0,0 @@
-#ifndef ONEFLOW_DAG_DATA_NODE_H_
-#define ONEFLOW_DAG_DATA_NODE_H_
-
-#include "dag/dag_node.h"
-
-namespace oneflow {
-
-class DataNode : public DagNode {
- public:
-  DISALLOW_COPY_AND_MOVE(DataNode);
-  virtual ~DataNode() = default;
- 
- protected:
-  DataNode() = default;
-  void Init() {
-    DagNode::Init();
-  }
-
- private:
-
-};
-
-} // namespace oneflow
-
-#endif // ONEFLOW_DAG_DATA_NODE_H_
diff --git a/oneflow/dag/logical_dag.cpp b/oneflow/dag/logical_dag.cpp
index e9ff6478e13cdf7ba060bac4ec85d7539b01972f..3678f5f4d25a8c87aaa264e6b84db79f3d7205e8 100644
--- a/oneflow/dag/logical_dag.cpp
+++ b/oneflow/dag/logical_dag.cpp
@@ -1,4 +1,5 @@
 #include "dag/logical_dag.h"
+#include "glog/logging.h"
 #include "layer/layer_desc_factory.h"
 
 namespace oneflow {
@@ -8,27 +9,75 @@ void LogicalDag::Init(const std::string& dag_name,
                       const Strategy& strategy_conf) {
   Dag::Init(dag_name);
   BuildDagStruct(dl_net_conf);
-  FillNodeWithPlacement(strategy_conf);
+  FillNodeWithParallelConf(strategy_conf);
+}
+
+// BlobNameInDag = LayerName/BlobNameInLayer
+// BlobNameInDagIf means Blob is the input of layer
+// BlobNameInDagOf means Blob is the output of layer
+static std::string BlobNameInDag2BlobNameInLayer(
+    const std::string& blob_name_in_dag) {
+  size_t slash_pos = blob_name_in_dag.find('/');
+  CHECK(slash_pos != std::string::npos);
+  return blob_name_in_dag.substr(slash_pos + 1);
 }
 
 void LogicalDag::BuildDagStruct(const DLNetConf& dl_net_conf) {
+  // This function only execute few times, so it is ok to declare it
+  std::unordered_map<std::string, LogicalDataNode*> blob_name_indag_of2ptr;
+  // Process Layer
   for (int layer_i = 0; layer_i < dl_net_conf.layer_conf_size(); ++layer_i) {
     const LayerConf& cur_layer_conf = dl_net_conf.layer_conf(layer_i);
     // Construct op node
     LogicalOpNode* cur_op_node = NewLogicalOpNode();
     cur_op_node->mutable_layer_desc() =
         LayerDescFactory::singleton().ConstructLayerDesc(cur_layer_conf);
-    // Construct input data node
-    for (const std::string& input_blob_name
+    // Connect input data node
+    for (const std::string& blob_name_in_dag_if
         : cur_op_node->layer_desc().data_blob_desc_set().input_blob_names()) {
-      input_blob_name.find('/');
+      std::string blob_name_in_layer =
+          BlobNameInDag2BlobNameInLayer(blob_name_in_dag_if);
+      std::string blob_name_indag_of =
+          GetStringValueFromPbMessage(cur_layer_conf, blob_name_in_layer);
+      auto data_node_it = blob_name_indag_of2ptr.find(blob_name_indag_of);
+      CHECK(data_node_it != blob_name_indag_of2ptr.end());
+      cur_op_node->AddPredecessor(data_node_it->second);
+    }
+    // Construct and connect output data node
+    for (const std::string& blob_name_indag_of
+        : cur_op_node->layer_desc().data_blob_desc_set().output_blob_names()) {
+      LogicalDataNode* data_node = NewLogicalDataNode();
+      bool insert_success =
+          blob_name_indag_of2ptr.emplace(blob_name_indag_of, data_node).second;
+      CHECK_EQ(insert_success, true);
+      data_node->AddPredecessor(cur_op_node);
     }
-    // Construct output data node
   }
+  blob_name_indag_of2ptr.clear();
+  // Post Processing
+  ConnectStartAndStop();
 }
 
-void FillNodeWithPlacement(const Strategy& strategy_conf) {
-  // TODO
+void LogicalDag::FillNodeWithParallelConf(const Strategy& strategy_conf) {
+  // This function only execute few times, so it is ok to declare it
+  std::unordered_map<std::string, LogicalOpNode*> layer_name2op_node;
+  for (const std::unique_ptr<OpNode>& op_node : op_node_vec()) {
+    auto logical_op_node_ptr = dynamic_cast<LogicalOpNode*> (op_node.get());
+    CHECK_NOTNULL(logical_op_node_ptr);
+    std::string layer_name = logical_op_node_ptr->layer_desc().layer_name();
+    bool emplace_success =
+        layer_name2op_node.emplace(layer_name, logical_op_node_ptr).second;
+    CHECK_EQ(emplace_success, true);
+  }
+  for (int gid = 0; gid < strategy_conf.placement_group_vec_size(); ++gid) {
+    const PlacementGroup& cur_group = strategy_conf.placement_group_vec(gid);
+    for (int li = 0; li < cur_group.layer_name_vec_size(); ++li) {
+      const std::string& layer_name = cur_group.layer_name_vec(li);
+      auto it = layer_name2op_node.find(layer_name);
+      CHECK(it != layer_name2op_node.end());
+      it->second->mutable_parallel_conf() = cur_group.parallel_conf();
+    }
+  }
 }
 
 } // namespace oneflow
diff --git a/oneflow/dag/logical_dag.h b/oneflow/dag/logical_dag.h
index eb9a742896bb2326d8b4d64b36c6f3c9b786d871..6326ca4b9f5b33d9faa7efffbd41aa0b092521b2 100644
--- a/oneflow/dag/logical_dag.h
+++ b/oneflow/dag/logical_dag.h
@@ -3,13 +3,58 @@
 
 #include <memory>
 #include "dag/dag.h"
-#include "dag/logical_data_node.h"
-#include "dag/logical_op_node.h"
+#include "layer/base_layer_desc.h"
 #include "job/dlnet_conf.pb.h"
 #include "job/strategy.pb.h"
 
 namespace oneflow {
 
+class LogicalDataNode : public DataNode {
+ public:
+  DISALLOW_COPY_AND_MOVE(LogicalDataNode);
+  LogicalDataNode() = default;
+  ~LogicalDataNode() = default;
+
+  void Init() {
+    DataNode::Init();
+    // struct style
+  }
+  
+ private:
+
+};
+
+class LogicalOpNode : public OpNode {
+ public:
+  DISALLOW_COPY_AND_MOVE(LogicalOpNode);
+  LogicalOpNode() = default;
+  ~LogicalOpNode() = default;
+
+  void Init() {
+    OpNode::Init();
+    // struct style
+  }
+
+  const BaseLayerDesc& layer_desc() const {
+    return *(layer_desc_.get());
+  }
+  const ParallelConf& parallel_conf() const {
+    return parallel_conf_;
+  }
+
+  std::unique_ptr<BaseLayerDesc>& mutable_layer_desc() {
+    return layer_desc_;
+  }
+  ParallelConf& mutable_parallel_conf() {
+    return parallel_conf_;
+  }
+
+ private:
+  std::unique_ptr<BaseLayerDesc> layer_desc_;
+  ParallelConf parallel_conf_;
+
+};
+
 class LogicalDag : public Dag {
  public:
   DISALLOW_COPY_AND_MOVE(LogicalDag);
@@ -22,25 +67,22 @@ class LogicalDag : public Dag {
 
  private:
   void BuildDagStruct(const DLNetConf& dl_net_conf);
-  void FillNodeWithPlacement(const Strategy& strategy_conf);
+  void FillNodeWithParallelConf(const Strategy& strategy_conf);
 
   LogicalDataNode* NewLogicalDataNode() {
-    std::unique_ptr<LogicalDataNode> new_node(new LogicalDataNode);
-    new_node->Init();
-    logical_data_node_vec_.push_back(std::move(new_node));
-    return logical_data_node_vec_.back().get();
+    LogicalDataNode* ret_ptr = new LogicalDataNode;
+    ret_ptr->Init();
+    RegisterDataNode(std::unique_ptr<LogicalDataNode> (ret_ptr));
+    return ret_ptr;
   }
 
   LogicalOpNode* NewLogicalOpNode() {
-    std::unique_ptr<LogicalOpNode> new_node(new LogicalOpNode);
-    new_node->Init();
-    logical_op_node_vec_.push_back(std::move(new_node));
-    return logical_op_node_vec_.back().get();
+    LogicalOpNode* ret_ptr = new LogicalOpNode;
+    ret_ptr->Init();
+    RegisterOpNode(std::unique_ptr<LogicalOpNode> (ret_ptr));
+    return ret_ptr;
   }
 
-  std::vector<std::unique_ptr<LogicalDataNode>> logical_data_node_vec_;
-  std::vector<std::unique_ptr<LogicalOpNode>> logical_op_node_vec_;
-
 };
 
 } // namespace oneflow
diff --git a/oneflow/dag/logical_data_node.h b/oneflow/dag/logical_data_node.h
deleted file mode 100644
index 382008457038aedd06cb9673622b3a90a201bf00..0000000000000000000000000000000000000000
--- a/oneflow/dag/logical_data_node.h
+++ /dev/null
@@ -1,34 +0,0 @@
-#ifndef ONEFLOW_LOGICAL_DATA_NODE_H_
-#define ONEFLOW_LOGICAL_DATA_NODE_H_
-
-#include "dag/data_node.h"
-#include "blob/blob_descriptor.h"
-
-namespace oneflow {
-
-class LogicalDataNode : public DataNode {
- public:
-  DISALLOW_COPY_AND_MOVE(LogicalDataNode);
-  LogicalDataNode() = default;
-  ~LogicalDataNode() = default;
-
-  void Init() {
-    DataNode::Init();
-    // struct style
-  }
-  
-  const BlobDescriptor& blob_desc() const {
-    return blob_desc_;
-  }
-  BlobDescriptor& mutable_blob_desc() {
-    return blob_desc_;
-  }
-
- private:
-  BlobDescriptor blob_desc_;
-
-};
-
-} // namespace oneflow
-
-#endif // ONEFLOW_LOGICAL_DATA_NODE_H_
diff --git a/oneflow/dag/logical_op_node.h b/oneflow/dag/logical_op_node.h
deleted file mode 100644
index 30f8607226373b06e68bb27a98a939aa02cfefdb..0000000000000000000000000000000000000000
--- a/oneflow/dag/logical_op_node.h
+++ /dev/null
@@ -1,43 +0,0 @@
-#ifndef ONEFLOW_LOGICAL_OP_NODE_H_
-#define ONEFLOW_LOGICAL_OP_NODE_H_
-
-#include "dag/op_node.h"
-#include "layer/base_layer_desc.h"
-#include "job/strategy.pb.h"
-
-namespace oneflow {
-
-class LogicalOpNode : public OpNode {
- public:
-  DISALLOW_COPY_AND_MOVE(LogicalOpNode);
-  LogicalOpNode() = default;
-  ~LogicalOpNode() = default;
-
-  void Init() {
-    OpNode::Init();
-    // struct style
-  }
-
-  const BaseLayerDesc& layer_desc() const {
-    return *(layer_desc_.get());
-  }
-  const ParallelConf& parallel_conf() const {
-    return parallel_conf_;
-  }
-
-  std::unique_ptr<BaseLayerDesc>& mutable_layer_desc() {
-    return layer_desc_;
-  }
-  ParallelConf& mutable_parallel_conf() {
-    return parallel_conf_;
-  }
-
- private:
-  std::unique_ptr<BaseLayerDesc> layer_desc_;
-  ParallelConf parallel_conf_;
-
-};
-
-} // namespace oneflow
-
-#endif // ONEFLOW_LOGICAL_OP_NODE_H_
diff --git a/oneflow/dag/op_node.h b/oneflow/dag/op_node.h
deleted file mode 100644
index 39b8f27a52b99416b4f9c91c2e14d4cfe9dd742f..0000000000000000000000000000000000000000
--- a/oneflow/dag/op_node.h
+++ /dev/null
@@ -1,26 +0,0 @@
-#ifndef ONEFLOW_DAG_OP_NODE_H_
-#define ONEFLOW_DAG_OP_NODE_H_
-
-#include "dag/dag_node.h"
-
-namespace oneflow {
-
-class OpNode : public DagNode {
- public:
-  DISALLOW_COPY_AND_MOVE(OpNode);
-
-  virtual ~OpNode() = default;
-
- protected:
-  OpNode() = default;
-  void Init() {
-    DagNode::Init();
-  }
- 
- private:
-
-};
-
-} // namespace oneflow
-
-#endif // ONEFLOW_DAG_OP_NODE_H_