diff --git a/paddle/fluid/framework/ir/CMakeLists.txt b/paddle/fluid/framework/ir/CMakeLists.txt
index 28231a53bad50fe9f19cfe3e73c3dc09aa3762cf..4cf973253cc4f1f22d2fc578a1ac3a8c95e479c9 100644
--- a/paddle/fluid/framework/ir/CMakeLists.txt
+++ b/paddle/fluid/framework/ir/CMakeLists.txt
@@ -53,6 +53,7 @@ set(GLOB_PASS_LIB ${PASS_LIBRARY} CACHE INTERNAL "Global PASS library")
 
 cc_library(pass_builder SRCS pass_builder.cc DEPS pass)
 
+cc_test(node_test SRCS node_test.cc DEPS node)
 cc_test(pass_test SRCS pass_test.cc DEPS graph pass graph_helper)
 cc_test(graph_test SRCS graph_test.cc DEPS graph graph_helper op_registry)
 cc_test(graph_helper_test SRCS graph_helper_test.cc DEPS graph graph_helper op_registry)
diff --git a/paddle/fluid/framework/ir/node.h b/paddle/fluid/framework/ir/node.h
index b8764e256c15d54ada4d1c8c33b485f7b3279087..98650c23f753a49c017c03036006da98710928a1 100644
--- a/paddle/fluid/framework/ir/node.h
+++ b/paddle/fluid/framework/ir/node.h
@@ -27,7 +27,24 @@ namespace paddle {
 namespace framework {
 namespace ir {
 
-// Node should normally created by Graph::CreateXXXNode().
+// Node should only created by Graph::CreateXXXNode().
+// 1. Every Node should be part of a graph. No dangling Node exists.
+// 2. Node only contains members necessary for building graph structure.
+//    It doesn't contain other unrelated members, such as device, etc.
+//
+// Sometimes, for specific usages, Node needs to have additional members,
+// such as device_placement, version in order to be executed. It is suggested
+// to use composition pattern.
+//
+// class RunnableOp {
+//    RunnableOp(ir::Node* n) : n_(n) { n_.WrappedBy(this); }
+//
+//    int any_thing_;
+// }
+//
+// RunnableOp is owned by the ir::Node that composes it. In other words.
+// ir::Node will be responsible for deleting RunnableOp, say, when ir::Node
+// is deleted from the graph.
 class Node {
  public:
   virtual ~Node() {
@@ -53,6 +70,7 @@ class Node {
     return op_desc_.get();
   }
 
+  // Set the `wrapper` that wraps the Node. `wrapper` is owned by Node.
   template <typename T>
   void WrappedBy(T* wrapper) {
     if (!wrapper_.empty()) {
@@ -63,11 +81,13 @@ class Node {
     wrapper_type_ = std::type_index(typeid(T));
   }
 
+  // Return a reference to the `wrapper`.
   template <typename T>
   T& Wrapper() {
     return *boost::any_cast<T*>(wrapper_);
   }
 
+  // Test if the Node is wrapped by type T.
   template <typename T>
   bool IsWrappedBy() {
     return std::type_index(typeid(T)) == wrapper_type_;
diff --git a/paddle/fluid/framework/ir/node_test.cc b/paddle/fluid/framework/ir/node_test.cc
new file mode 100644
index 0000000000000000000000000000000000000000..694efadda078169c993457181c00f7b357a09e87
--- /dev/null
+++ b/paddle/fluid/framework/ir/node_test.cc
@@ -0,0 +1,80 @@
+/* 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 <string>
+#include "gtest/gtest.h"
+#include "paddle/fluid/framework/ir/graph.h"
+#include "paddle/fluid/framework/ir/pass.h"
+
+namespace paddle {
+namespace framework {
+namespace ir {
+
+class RunnableOp {
+ public:
+  RunnableOp(Node* node, bool* alive) : node_(node), alive_(alive) {
+    node_->WrappedBy(this);
+  }
+
+  virtual ~RunnableOp() { *alive_ = false; }
+
+ private:
+  Node* node_;
+  bool* alive_;
+};
+
+class RunnableOp2 {
+ public:
+  RunnableOp2(Node* node, bool* alive) : node_(node), alive_(alive) {
+    node_->WrappedBy(this);
+  }
+
+  virtual ~RunnableOp2() { *alive_ = false; }
+
+ private:
+  Node* node_;
+  bool* alive_;
+};
+
+TEST(NodeTest, Basic) {
+  bool alive1 = true;
+  bool alive2 = true;
+  std::unique_ptr<Node> n1(CreateNodeForTest("n1", Node::Type::kVariable));
+  std::unique_ptr<Node> n2(CreateNodeForTest("n2", Node::Type::kVariable));
+
+  EXPECT_FALSE(n1->IsWrappedBy<RunnableOp>());
+  EXPECT_FALSE(n1->IsWrappedBy<RunnableOp2>());
+  EXPECT_FALSE(n2->IsWrappedBy<RunnableOp>());
+  EXPECT_FALSE(n2->IsWrappedBy<RunnableOp2>());
+
+  new RunnableOp(n1.get(), &alive1);
+  new RunnableOp2(n2.get(), &alive2);
+
+  EXPECT_TRUE(n1->IsWrappedBy<RunnableOp>());
+  EXPECT_FALSE(n1->IsWrappedBy<RunnableOp2>());
+  EXPECT_FALSE(n2->IsWrappedBy<RunnableOp>());
+  EXPECT_TRUE(n2->IsWrappedBy<RunnableOp2>());
+
+  EXPECT_TRUE(alive1);
+  EXPECT_TRUE(alive2);
+
+  n1.reset(nullptr);
+  n2.reset(nullptr);
+  EXPECT_FALSE(alive1);
+  EXPECT_FALSE(alive2);
+}
+
+}  // namespace ir
+}  // namespace framework
+}  // namespace paddle