diff --git a/paddle/fluid/framework/communicator.h b/paddle/fluid/framework/communicator.h
deleted file mode 100644
index 0e90ba02e6e030fa9b1c4f91fc76a14e1c145455..0000000000000000000000000000000000000000
--- a/paddle/fluid/framework/communicator.h
+++ /dev/null
@@ -1,53 +0,0 @@
-/* Copyright (c) 2016 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 <cstdint>
-#include <cstring>
-#include <memory>
-#include <typeindex>
-#include <vector>
-#include "paddle/fluid/framework/data_layout.h"
-#include "paddle/fluid/framework/ddim.h"
-#include "paddle/fluid/framework/framework.pb.h"
-#include "paddle/fluid/memory/memory.h"
-#include "paddle/fluid/platform/device_context.h"
-#include "paddle/fluid/platform/enforce.h"
-#include "paddle/fluid/platform/place.h"
-
-namespace paddle {
-
-namespace framework {
-
-class Communicator {
- public:
-  Communicator() {}
-  ~Communicator() {}
-
-  // send grad
-  void send() {}
-
-  void receive() {}
-
-  void prefetch() {}
-
-  void wait() {}
-
- private:
-  std::unique_ptr<std::thread> communicate_thread_;
-};
-
-}  // namespace framework
-}  // namespace paddle
diff --git a/paddle/fluid/framework/variable_helper.cc b/paddle/fluid/framework/variable_helper.cc
index fc4525549caeebb06dea766ccb123b5ebc6d5b13..d59f3ea7dcc2fc7e63355c3d063873f42e5310ca 100644
--- a/paddle/fluid/framework/variable_helper.cc
+++ b/paddle/fluid/framework/variable_helper.cc
@@ -27,7 +27,7 @@ limitations under the License. */
 
 namespace paddle {
 namespace framework {
-void InitializeVariable(Variable* var, proto::VarType::Type var_type) {
+void InitializeVariable(Variable *var, proto::VarType::Type var_type) {
   if (var_type == proto::VarType::LOD_TENSOR) {
     var->GetMutable<LoDTensor>();
   } else if (var_type == proto::VarType::SELECTED_ROWS) {
@@ -37,7 +37,7 @@ void InitializeVariable(Variable* var, proto::VarType::Type var_type) {
   } else if (var_type == proto::VarType::FETCH_LIST) {
     var->GetMutable<FeedFetchList>();
   } else if (var_type == proto::VarType::STEP_SCOPES) {
-    var->GetMutable<std::vector<framework::Scope*>>();
+    var->GetMutable<std::vector<framework::Scope *>>();
   } else if (var_type == proto::VarType::LOD_RANK_TABLE) {
     var->GetMutable<LoDRankTable>();
   } else if (var_type == proto::VarType::LOD_TENSOR_ARRAY) {
@@ -56,5 +56,27 @@ void InitializeVariable(Variable* var, proto::VarType::Type var_type) {
         var_type);
   }
 }
+
+void CopyVariable(const Variable &src_var, Variable *dst_var) {
+  // only support cpu now
+  auto cpu_place = platform::CPUPlace();
+
+  if (src_var.IsType<framework::LoDTensor>()) {
+    auto *tmp_grad_tensor = dst_var->GetMutable<framework::LoDTensor>();
+    auto &src_tensor = src_var.Get<framework::LoDTensor>();
+    tmp_grad_tensor->set_lod(src_tensor.lod());
+    framework::TensorCopy(src_tensor, cpu_place, tmp_grad_tensor);
+  } else if (src_var.IsType<framework::SelectedRows>()) {
+    auto &src_slr = src_var.Get<framework::SelectedRows>();
+    auto *tmp_grad_slr = dst_var->GetMutable<framework::SelectedRows>();
+    tmp_grad_slr->set_rows(src_slr.rows());
+    tmp_grad_slr->set_height(src_slr.height());
+    auto &src_t = src_slr.value();
+    auto *dst_t = tmp_grad_slr->mutable_value();
+    framework::TensorCopy(src_t, cpu_place, dst_t);
+  } else {
+    PADDLE_THROW("unknown var type to copy");
+  }
+}
 }  // namespace framework
 }  // namespace paddle
diff --git a/paddle/fluid/framework/variable_helper.h b/paddle/fluid/framework/variable_helper.h
index 0e0c72c3621dce0a6b372f9a9110a63fbc0a1d71..f8e90d53967524c37e68f7dc647fb597322aa3c4 100644
--- a/paddle/fluid/framework/variable_helper.h
+++ b/paddle/fluid/framework/variable_helper.h
@@ -17,6 +17,7 @@ limitations under the License. */
 #include "paddle/fluid/framework/variable.h"
 namespace paddle {
 namespace framework {
-void InitializeVariable(Variable *var, proto::VarType::Type var_type);
+void InitializeVariable(Variable* var, proto::VarType::Type var_type);
+void CopyVariable(const Variable& src_var, Variable* dst_var);
 }
 }
diff --git a/paddle/fluid/operators/distributed/CMakeLists.txt b/paddle/fluid/operators/distributed/CMakeLists.txt
index 231f4b3bc41e1bf3f0a7d52217d3234df0a68967..22f44c42179bc59140c974b6255ff4555419c21b 100644
--- a/paddle/fluid/operators/distributed/CMakeLists.txt
+++ b/paddle/fluid/operators/distributed/CMakeLists.txt
@@ -54,6 +54,7 @@ cc_test(varhandle_test SRCS varhandle_test.cc DEPS profiler scope)
 cc_library(parameter_prefetch SRCS parameter_prefetch.cc DEPS sendrecvop_rpc memory)
 cc_library(parameter_send SRCS parameter_send.cc DEPS sendrecvop_rpc memory)
 cc_library(parameter_recv SRCS parameter_recv.cc DEPS sendrecvop_rpc memory)
+cc_library(communicator SRCS communicator.cc DEPS scope selected_rows tensor variable_helper selected_rows_functor)
 if(WITH_GPU)
     cc_test(collective_server_test SRCS collective_server_test.cc 
         DEPS sendrecvop_rpc executor ${RPC_DEPS}
diff --git a/paddle/fluid/operators/distributed/communicator.cc b/paddle/fluid/operators/distributed/communicator.cc
new file mode 100644
index 0000000000000000000000000000000000000000..fb9ecfa808167261da5cef4cc6e4950552634e1d
--- /dev/null
+++ b/paddle/fluid/operators/distributed/communicator.cc
@@ -0,0 +1,113 @@
+/* Copyright (c) 2019 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/operators/distributed/communicator.h"
+
+#include "paddle/fluid/framework/selected_rows.h"
+#include "paddle/fluid/framework/tensor_util.h"
+#include "paddle/fluid/framework/variable_helper.h"
+#include "paddle/fluid/operators/distributed/parameter_recv.h"
+#include "paddle/fluid/operators/distributed/parameter_send.h"
+#include "paddle/fluid/operators/math/selected_rows_functor.h"
+
+namespace paddle {
+namespace operators {
+namespace distributed {
+
+static void MergeVars(const std::string &var_name,
+                      const std::vector<std::shared_ptr<Variable>> &vars,
+                      Scope *scope) {
+  PADDLE_ENFORCE(!vars.empty(), "should have value to merge!");
+  auto cpu_place = platform::CPUPlace();
+  auto &var0 = vars[0];
+  auto *out_var = scope->Var(var_name);
+  if (var0->IsType<framework::LoDTensor>()) {
+    auto *out_t = out_var->GetMutable<framework::LoDTensor>();
+    auto *out_ptr = out_t->mutable_data<float>(
+        var0->Get<framework::LoDTensor>().dims(), cpu_place);
+    auto numel = out_t->numel();
+    for (auto i = 0; i < numel; ++i) {
+      out_ptr[i] = 0;
+      for (auto &var : vars) {
+        auto &var_t = var->Get<framework::LoDTensor>();
+        PADDLE_ENFORCE_EQ(var_t.numel(), numel, "should have the same dims");
+        out_ptr[i] += var_t.data<float>()[i];
+      }
+    }
+  } else if (var0->IsType<framework::SelectedRows>()) {
+    auto *out_slr = out_var->GetMutable<framework::SelectedRows>();
+    std::vector<const paddle::framework::SelectedRows *> inputs;
+    inputs.reserve(vars.size());
+    for (auto &var : vars) {
+      inputs.push_back(&var->Get<framework::SelectedRows>());
+    }
+    math::scatter::MergeAdd<paddle::platform::CPUDeviceContext, float>
+        merge_add;
+    auto dev_ctx = paddle::platform::CPUDeviceContext();
+    merge_add(dev_ctx, inputs, out_slr, false);
+  } else {
+    PADDLE_THROW("unsupported var type!");
+  }
+}
+
+void Communicator::SendThread() {
+  for (auto &iter : send_varname_to_queue_) {
+    auto &var_name = iter.first;
+    VLOG(3) << "merge var " << var_name << " and send";
+    auto &var_queue = iter.second;
+    std::vector<std::shared_ptr<Variable>> vars;
+    const size_t max_merge_var_num = 20;
+    size_t merged_var_num = 0;
+    while (var_queue->Size() > 0 && merged_var_num < max_merge_var_num) {
+      vars.push_back(var_queue->Pop());
+      merged_var_num++;
+    }
+    MergeVars(var_name, vars, send_scope_.get());
+    auto send_functor = distributed::ParameterSend<float>();
+    //    send_functor(var_name, send_varname_to_ctx_[var_name], exe_ctx,
+    //    send_scope_, true);
+  }
+}
+
+void Communicator::RecvThread() {
+  // parallel run recv graph
+  for (auto &iter : recv_varname_to_ctx_) {
+    auto &var_name = iter.first;
+    VLOG(3) << "recv var " << iter.first;
+    auto recv_functor = distributed::ParameterRecv<float>();
+    //    recv_functor(var_name, iter.second, exe_ctx, recv_scope_);
+  }
+}
+
+void Communicator::Send(const std::string &var_name,
+                        const framework::Scope &scope) {
+  // push var into send queue by var_name
+  auto *grad_var = scope.FindVar(var_name);
+  PADDLE_ENFORCE(grad_var->IsInitialized(), "grad var should be inited");
+  auto tmp_grad_var = std::make_shared<Variable>();
+  framework::CopyVariable(*grad_var, tmp_grad_var.get());
+  send_varname_to_queue_[var_name]->Push(tmp_grad_var);
+}
+
+void Communicator::Start() {
+  // start send and recv thread
+  send_thread_.reset(
+      new std::thread(std::bind(&Communicator::SendThread, this)));
+  recv_thread_.reset(
+      new std::thread(std::bind(&Communicator::RecvThread, this)));
+}
+
+}  // namespace distributed
+}  // namespace operators
+}  // namespace paddle
diff --git a/paddle/fluid/operators/distributed/communicator.h b/paddle/fluid/operators/distributed/communicator.h
new file mode 100644
index 0000000000000000000000000000000000000000..614d6ade81ddb8a64dfb8139e779d811d234bfe8
--- /dev/null
+++ b/paddle/fluid/operators/distributed/communicator.h
@@ -0,0 +1,129 @@
+/* Copyright (c) 2019 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 <deque>
+#include <memory>
+#include <string>
+#include <vector>
+
+#include "paddle/fluid/framework/scope.h"
+#include "paddle/fluid/framework/variable.h"
+#include "paddle/fluid/operators/distributed/rpc_common.h"
+#include "paddle/fluid/platform/device_context.h"
+#include "paddle/fluid/platform/enforce.h"
+#include "paddle/fluid/platform/place.h"
+
+namespace paddle {
+namespace operators {
+namespace distributed {
+
+using Scope = framework::Scope;
+using Variable = framework::Variable;
+
+template <typename T>
+class BlockingQueue {
+ public:
+  explicit BlockingQueue(size_t capacity) : capacity_(capacity) {
+    PADDLE_ENFORCE_GT(capacity_, 0, "The capacity must be greater than 0.");
+  }
+
+  bool Push(const T& elem) {
+    std::unique_lock<std::mutex> lock(mutex_);
+    send_cv_.wait(lock, [&] { return queue_.size() < capacity_; });
+    PADDLE_ENFORCE_LT(queue_.size(), capacity_);
+    queue_.push_back(elem);
+    recv_cv_.notify_one();
+    return true;
+  }
+
+  bool Push(T&& elem) {
+    std::unique_lock<std::mutex> lock(mutex_);
+    send_cv_.wait(lock, [&] { return queue_.size() < capacity_; });
+    PADDLE_ENFORCE_LT(queue_.size(), capacity_);
+    queue_.emplace_back(std::move(elem));
+    recv_cv_.notify_one();
+    return true;
+  }
+
+  T Pop() {
+    std::unique_lock<std::mutex> lock(mutex_);
+    recv_cv_.wait(lock, [=] { return !queue_.empty(); });
+    T rc(std::move(queue_.front()));
+    queue_.pop_front();
+    return rc;
+  }
+
+  size_t Cap() const {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return capacity_;
+  }
+
+  size_t Size() const {
+    std::lock_guard<std::mutex> lock(mutex_);
+    return queue_.size();
+  }
+
+ private:
+  const size_t capacity_;
+  std::deque<T> queue_;
+
+  mutable std::mutex mutex_;
+  std::condition_variable recv_cv_;
+  std::condition_variable send_cv_;
+};
+
+class Communicator {
+ public:
+  Communicator(
+      const std::unordered_map<std::string, RpcContext>& send_varname_to_ctx,
+      const std::unordered_map<std::string, RpcContext>& recv_varname_to_ctx,
+      Scope* recv_scope)
+      : send_varname_to_ctx_(send_varname_to_ctx),
+        recv_varname_to_ctx_(recv_varname_to_ctx),
+        recv_scope_(recv_scope) {
+    // get all send information from graph, build vars_to_send
+    send_scope_.reset(new Scope());
+    for (auto& iter : send_varname_to_ctx_) {
+      send_varname_to_queue_[iter.first] =
+          std::make_shared<BlockingQueue<std::shared_ptr<Variable>>>(10);
+    }
+  }
+
+  ~Communicator() {}
+
+  void Start();
+
+  // send grad
+  void Send(const std::string& var_name, const framework::Scope& scope);
+
+ private:
+  void SendThread();
+  void RecvThread();
+
+  std::unordered_map<std::string,
+                     std::shared_ptr<BlockingQueue<std::shared_ptr<Variable>>>>
+      send_varname_to_queue_;
+  std::unordered_map<std::string, RpcContext> send_varname_to_ctx_;
+  std::unordered_map<std::string, RpcContext> recv_varname_to_ctx_;
+  std::unique_ptr<std::thread> send_thread_;
+  std::unique_ptr<std::thread> recv_thread_;
+  Scope* recv_scope_;                  // should be global scope
+  std::unique_ptr<Scope> send_scope_;  // an independent scope
+};
+
+}  // namespace distributed
+}  // namespace operators
+}  // namespace paddle
diff --git a/paddle/fluid/operators/distributed/parameter_prefetch.cc b/paddle/fluid/operators/distributed/parameter_prefetch.cc
index 7434265929d51e571ba8a7ef20f441923c015340..539a038099752d110f0576c1db7ef0bad75e733c 100644
--- a/paddle/fluid/operators/distributed/parameter_prefetch.cc
+++ b/paddle/fluid/operators/distributed/parameter_prefetch.cc
@@ -39,7 +39,7 @@ using DDim = framework::DDim;
 
 static std::vector<std::vector<int64_t>> SplitIds(
     const std::vector<int64_t>& ids_vector,
-    const std::vector<int64_t>& height_section, framework::Scope* scope) {
+    const std::vector<int64_t>& height_section) {
   std::set<int64_t> all_ids;
   for (auto id : ids_vector) {
     all_ids.insert(id);
@@ -203,7 +203,7 @@ void prefetch(const std::string& id_name, const std::string& out_name,
 #endif
   }
 
-  auto splited_ids = SplitIds(ids_vector, height_sections, local_scope);
+  auto splited_ids = SplitIds(ids_vector, height_sections);
   SplitIdsIntoMultipleVarsBySection(in_var_names, height_sections, splited_ids,
                                     local_scope);
 
diff --git a/paddle/fluid/operators/distributed/parameter_recv.cc b/paddle/fluid/operators/distributed/parameter_recv.cc
index 2664a89ed6d7345a8c7c014f789a9e817d75ad28..b8d3b77ae41e5846ec752ce8513dbbf17dde7735 100644
--- a/paddle/fluid/operators/distributed/parameter_recv.cc
+++ b/paddle/fluid/operators/distributed/parameter_recv.cc
@@ -73,7 +73,7 @@ void ParameterRecv<T>::operator()(const std::string &var_name,
       PADDLE_ENFORCE(rets[i]->Wait(), "internal error in RPCClient");
     }
   } else {
-    PADDLE_THROW("unsupported var type to send!");
+    PADDLE_THROW("unsupported var type to recv!");
   }
 
   // concat recved tensor into one var
diff --git a/paddle/fluid/operators/distributed/rpc_common.h b/paddle/fluid/operators/distributed/rpc_common.h
new file mode 100644
index 0000000000000000000000000000000000000000..dc50414b9af5132a282c81f85046fa321e6d94a3
--- /dev/null
+++ b/paddle/fluid/operators/distributed/rpc_common.h
@@ -0,0 +1,33 @@
+/* Copyright (c) 2019 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 <vector>
+
+namespace paddle {
+namespace operators {
+namespace distributed {
+
+struct RpcContext {
+  std::string var_name;
+  std::vector<std::string> splited_var_names;
+  std::vector<std::string> epmap;
+  std::vector<int64_t> height_sections;
+};
+
+}  // namespace distributed
+}  // namespace operators
+}  // namespace paddle
diff --git a/paddle/fluid/operators/math/selected_rows_functor.h b/paddle/fluid/operators/math/selected_rows_functor.h
index 222d761ef91d8aee4843d717dabba7edf131f8dc..db0ee9bc1695f7b1a55b4d111dc470b462210963 100644
--- a/paddle/fluid/operators/math/selected_rows_functor.h
+++ b/paddle/fluid/operators/math/selected_rows_functor.h
@@ -95,7 +95,7 @@ struct MergeAdd {
 
 enum class ScatterOps { ASSIGN, ADD, SUB, SUBBY, MUL, DIV, DIVBY };
 
-// out = seleted_rows_in / tensor
+// out = selected_rows_in / tensor
 template <typename DeviceContext, typename T>
 struct UpdateToTensor {
   void operator()(const DeviceContext& context, const ScatterOps& op,