diff --git a/paddle/framework/CMakeLists.txt b/paddle/framework/CMakeLists.txt
index 39cfb4623795e8dff47b9f69a16ee70361dd81ab..e6e3b79d7bd1129e102fde780c8e609a16745e75 100644
--- a/paddle/framework/CMakeLists.txt
+++ b/paddle/framework/CMakeLists.txt
@@ -18,4 +18,4 @@ add_custom_target(framework_py_proto_init ALL COMMAND ${CMAKE_COMMAND} -E touch
 add_dependencies(framework_py_proto framework_py_proto_init)
 
 proto_library(net_proto SRCS net_proto.proto DEPS op_proto)
-#cc_library(net SRCS net.cc DEPS net_proto attr_type op_proto)
+cc_library(net SRCS net.cc DEPS net_proto attr_type op_proto)
diff --git a/paddle/framework/net.cc b/paddle/framework/net.cc
index 20c0aef049ceb6f0617904eb757a904f83ee4260..f0c128d554b296d7fe5c6818d3911aaee5c0adce 100644
--- a/paddle/framework/net.cc
+++ b/paddle/framework/net.cc
@@ -11,7 +11,10 @@ void PlainNet::InferShape(Scope* scope) {
   }
 }
 
-void PlainNet::Run(Scope* scope) const {}
-
+void PlainNet::Run(Scope* scope, DeviceContext* ctx) {
+  for (auto& op : ops_) {
+    op.Run(ctx);
+  }
+}
 }  // namespace framework
 }  // namespace paddle
diff --git a/paddle/framework/net.h b/paddle/framework/net.h
index ef5013349196a50f9950469f8495c6b3e166a049..b2894320dafdfaf9b8e0bffc8c863a2caae35a61 100644
--- a/paddle/framework/net.h
+++ b/paddle/framework/net.h
@@ -17,9 +17,11 @@
 #include "paddle/framework/net_proto.pb.h"
 #include "paddle/framework/op_proto.pb.h"
 #include "paddle/framework/scope.h"
+#include "paddle/platform/device_context.h"
 
 namespace paddle {
 namespace framework {
+using namespace paddle::platform;
 
 // operator's index stored in a network.
 typedef int OpIndex;
@@ -30,15 +32,13 @@ typedef int OpIndex;
  */
 
 struct OpDesc;
-struct OpDef;
-struct OpContext;
 struct OpAttrs {};
 
 class Operator {
  public:
   Operator(const OpDesc &def) {}
   void InferShape() {}
-  void Run() {}
+  void Run(DeviceContext *ctx) {}
 };
 
 /**
@@ -69,12 +69,12 @@ class Net {
    * environment for ops. `begin` and `end` specify the scope of `ops_` to run,
    * If no positive indexes are provided, all operators in `ops_` will run.
    */
-  virtual void Run(Scope *scope) const = 0;
+  virtual void Run(Scope *scope, DeviceContext *ctx) = 0;
 
   /**
    * @brief Add an Operator according to `def`.
    */
-  virtual OpIndex AddOp(const OpDef &def) = 0;
+  virtual OpIndex AddOp(const OpProto &def) = 0;
 
   /**
    * @brief Add optimizer operators acctording to `attrs`.
@@ -123,12 +123,12 @@ class PlainNet : public Net {
    * scope will be used instead. If no OpContext is provicded, default context
    * will be used.
    */
-  virtual void Run(Scope *scope) const override;
+  virtual void Run(Scope *scope, DeviceContext *ctx) override;
 
   /**
    * @brief Add an operator to this network.
    */
-  virtual OpIndex AddOp(const OpDef &def) override;
+  virtual OpIndex AddOp(const OpProto &def) override;
 
   /**
    * @brief Add all optimizer operators related into the network.
diff --git a/paddle/framework/net_test.cc b/paddle/framework/net_test.cc
index 04f5efdf79bdcf724accc20a7b6365b003d61ff4..a8e31c1497519ce60da004bc0a3e52403593497c 100644
--- a/paddle/framework/net_test.cc
+++ b/paddle/framework/net_test.cc
@@ -19,6 +19,6 @@
 
 namespace paddle {
 namespace framework {
-class FakeFC : public OpBase {}
+class FakeFC : public Operator {}
 }  // namespace framework
 }  // namespace paddle
diff --git a/paddle/platform/device_context.h b/paddle/platform/device_context.h
index fcef0a5e3058f1c9d54f9e06a54a09286e2454fd..160eb4e12060b36c4fefba499d4e83b9aab92848 100644
--- a/paddle/platform/device_context.h
+++ b/paddle/platform/device_context.h
@@ -36,6 +36,7 @@ class DeviceContext {
 class CPUDeviceContext : public DeviceContext {};
 
 #ifndef PADDLE_ONLY_CPU
+
 class GPUPlaceGuard {
  public:
   explicit GPUPlaceGuard(GPUPlace new_place) : previous_(GetCurrentDeviceId()) {