diff --git a/paddle/framework/CMakeLists.txt b/paddle/framework/CMakeLists.txt
index 7ea17f7114c6558f5a786d02eeff1ba097a870ee..6caeb1be3a8f1d15df87f4b4f7a99bad352ec5b5 100644
--- a/paddle/framework/CMakeLists.txt
+++ b/paddle/framework/CMakeLists.txt
@@ -6,6 +6,4 @@ nv_test(dim_test SRCS dim_test.cu DEPS ddim)
 
 cc_test(variable_test SRCS variable_test.cc)
 
-# scope lib
-cc_library(scope SRCS scope.cc)
-cc_test(scope_test SRCS scope_test.cc DEPS scope)
+cc_test(scope_test SRCS scope_test.cc)
diff --git a/paddle/framework/scope.cc b/paddle/framework/scope.cc
deleted file mode 100644
index 72cb744707dd6f8ccf8fa02a818af4927d662f24..0000000000000000000000000000000000000000
--- a/paddle/framework/scope.cc
+++ /dev/null
@@ -1,50 +0,0 @@
-/* Copyright (c) 2016 PaddlePaddle Authors. All Rights Reserve.
-
-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/framework/scope.h"
-
-namespace paddle {
-namespace framework {
-
-Variable* Scope::CreateVariable(const std::string& name) {
-  if (!HasVariable(name)) {
-    vars_[name] = std::unique_ptr<Variable>(new Variable());
-  }
-  return GetVariable(name);
-}
-
-Variable* Scope::GetVarLocally(const std::string& name) const {
-  if (vars_.count(name)) {
-    return vars_.at(name).get();
-  }
-  return nullptr;
-}
-
-Variable* Scope::GetVariable(const std::string& name) const {
-  Variable* var = GetVarLocally(name);
-  if (var != nullptr) {
-    return var;
-  } else if (parent_ != nullptr) {
-    return parent_->GetVariable(name);
-  } else {
-    return nullptr;
-  }
-}
-
-bool Scope::HasVariable(const std::string& name) {
-  return (vars_.count(name) > 0 || (parent_ && parent_->HasVariable(name)));
-}
-
-}  // namespace framework
-}  // namespace paddle
diff --git a/paddle/framework/scope.h b/paddle/framework/scope.h
index a624fe3bbef3ae3c7671e6f549c2cb7c63def15f..2f8d6dbd9763220903d52d6f26aa769f08ad86bb 100644
--- a/paddle/framework/scope.h
+++ b/paddle/framework/scope.h
@@ -19,37 +19,58 @@ limitations under the License. */
 #include <vector>
 
 #include "paddle/framework/variable.h"
+#include "paddle/platform/assert.h"
 
 namespace paddle {
 namespace framework {
 
 /**
  * Scope is an association of a name to Variable. All variables belong to
- * `Scope`. You need to specify a scope to run a Net, i.e., `net.Run(&scope)`.
+ * Scope. You need to specify a scope to run a Net, i.e., `net.Run(&scope)`.
  * One net can run in different scopes and update different variable in the
  * scope.
  */
 class Scope {
  public:
-  Scope() {}
-
-  explicit Scope(const std::shared_ptr<Scope>& scope) : parent_(scope) {}
-
-  ~Scope() {}
-
-  // Create Variable in this Scope. Return error if Variable already been
-  // created.
-  Variable* CreateVariable(const std::string& name);
-
-  // Get Variable from this Scope, this function will recursive find Variable
-  // from it's parent scope. Return nullptr if not found.
-  Variable* GetVariable(const std::string& name) const;
-
-  // Find and return Variables in the scope it self.
-  Variable* GetVarLocally(const std::string& name) const;
-
-  // Find if there is a Variable in this scope and it's parent scope
-  bool HasVariable(const std::string& name);
+  explicit Scope(const std::shared_ptr<Scope>& parent = nullptr)
+      : parent_(parent) {}
+
+  /// Create Variable in this Scope. Failed if Variable already been
+  /// created.
+  Variable* CreateVariable(const std::string& name) {
+    PADDLE_ASSERT(!HasVariable(name));
+    vars_[name] = std::unique_ptr<Variable>(new Variable());
+    return GetVariable(name);
+  }
+
+  /// Get Variable from this Scope, this function will recursive find Variable
+  /// from it's parent scope. Return nullptr if not found.
+  Variable* GetVariable(const std::string& name) const {
+    auto it = vars_.find(name);
+    if (it != vars_.end()) {
+      return it->second.get();
+    } else if (parent_ != nullptr) {
+      return parent_->GetVariable(name);
+    } else {
+      return nullptr;
+    }
+  }
+
+  /// Get Variable from scope, if Variable is not exist, creat one and return.
+  Variable* GetOrCreateVariable(const std::string& name) {
+    auto var = GetVariable(name);
+    if (var) {
+      return var;
+    } else {
+      return CreateVariable(name);
+    }
+  }
+
+  /// Find if there is a Variable in this scope and it's parent scope
+  bool HasVariable(const std::string& name) const {
+    return (vars_.find(name) != vars_.end() ||
+            (parent_ && parent_->HasVariable(name)));
+  }
 
  private:
   std::unordered_map<std::string, std::unique_ptr<Variable>> vars_;
diff --git a/paddle/framework/scope_test.cc b/paddle/framework/scope_test.cc
index 25c144868b45da47f897caa7e0522590b80b6019..34ee21e1aaa11202f837a2a0cac239da2c0b2e66 100644
--- a/paddle/framework/scope_test.cc
+++ b/paddle/framework/scope_test.cc
@@ -28,12 +28,13 @@ TEST(Scope, Create) {
   EXPECT_EQ(var1, nullptr);
 
   Variable* var2 = scope->CreateVariable("a");
-  EXPECT_NE(var2, nullptr);
 
-  Variable* var3 = scope->CreateVariable("a");
+  ASSERT_DEATH({ scope->CreateVariable("a"); }, "");
+
+  Variable* var3 = scope->GetVariable("a");
   EXPECT_EQ(var2, var3);
 
-  Variable* var4 = scope->GetVariable("a");
+  Variable* var4 = scope->GetOrCreateVariable("a");
   EXPECT_EQ(var2, var4);
 }
 
@@ -47,9 +48,6 @@ TEST(Scope, Parent) {
   Variable* var0 = parent_scope_ptr->CreateVariable("a");
   EXPECT_NE(var0, nullptr);
 
-  Variable* var1 = scope->GetVarLocally("a");
-  EXPECT_EQ(var1, nullptr);
-
-  Variable* var2 = scope->GetVariable("a");
-  EXPECT_EQ(var2, var0);
-}
\ No newline at end of file
+  Variable* var1 = scope->GetVariable("a");
+  EXPECT_EQ(var0, var1);
+}