diff --git a/paddle/api/GradientMachine.cpp b/paddle/api/GradientMachine.cpp
index a64e70a6bd563a20f1da3549aeaa76454dfe3219..538ca2999f8f05afc45ac2d2f526133c8024f066 100644
--- a/paddle/api/GradientMachine.cpp
+++ b/paddle/api/GradientMachine.cpp
@@ -148,7 +148,8 @@ Arguments* GradientMachine::getLayerOutput(const std::string& layerName) const
     throw(UnsupportError) {
   auto nn = m->machine;
   if (nn) {
-    return Arguments::createByPaddleArgument(&nn->getLayerOutput(layerName));
+    auto arg = nn->getLayerOutput(layerName);
+    return Arguments::createByPaddleArgument(&arg);
   } else {
     throw UnsupportError();
   }
diff --git a/paddle/api/Trainer.cpp b/paddle/api/Trainer.cpp
index 29cf2aa4501de35d970c4d416d62343d39bb234a..84e4ca054abb0100a02c8a40e31c49c17684ef40 100644
--- a/paddle/api/Trainer.cpp
+++ b/paddle/api/Trainer.cpp
@@ -134,7 +134,8 @@ void Trainer::finishTestPeriod() { m->finishTestPeriod(); }
 Arguments* Trainer::getLayerOutput(const std::string& layerName) const {
   auto nn = this->m->getGradientMachine();
   CHECK(nn) << "trainerInternal_.getGradientMachine() is not NeuralNetwork";
-  return Arguments::createByPaddleArgument(&nn->getLayerOutput(layerName));
+  auto arg = nn->getLayerOutput(layerName);
+  return Arguments::createByPaddleArgument(&arg);
 }
 
 void Trainer::forwardOneBatch(size_t batchSize) {
diff --git a/paddle/gserver/gradientmachines/GradientMachine.h b/paddle/gserver/gradientmachines/GradientMachine.h
index ae39783c6b7ea64a5306d08f665ed7e53f2b58ca..bc2f2f8563526aa045ea89f15152ee2d639b5774 100644
--- a/paddle/gserver/gradientmachines/GradientMachine.h
+++ b/paddle/gserver/gradientmachines/GradientMachine.h
@@ -134,7 +134,7 @@ public:
     backward(callback);
   }
 
-  virtual const Argument& getLayerOutput(const std::string& layerName) {
+  virtual Argument getLayerOutput(const std::string& layerName) {
     return *((Argument*)nullptr);
   }
 
diff --git a/paddle/gserver/gradientmachines/MultiGradientMachine.cpp b/paddle/gserver/gradientmachines/MultiGradientMachine.cpp
index 6b11b0155e990d6eb740f744ffa3f3a086e3e1ed..123273f916f5d33e2543d9f5f28573c3b5761e28 100644
--- a/paddle/gserver/gradientmachines/MultiGradientMachine.cpp
+++ b/paddle/gserver/gradientmachines/MultiGradientMachine.cpp
@@ -282,8 +282,7 @@ void MultiGradientMachine::forwardBackward(const std::vector<Argument>& inArgs,
   backwardImp(callback);
 }
 
-const Argument& MultiGradientMachine::getLayerOutput(
-    const std::string& layerName) {
+Argument MultiGradientMachine::getLayerOutput(const std::string& layerName) {
   std::vector<Argument> args;
   args.reserve(threads_.size());
 
diff --git a/paddle/gserver/gradientmachines/MultiGradientMachine.h b/paddle/gserver/gradientmachines/MultiGradientMachine.h
index 9083230afd69e278b0343be1785edd01df3ad016..838a52b5153af63adbce5788824b9f541f22517c 100644
--- a/paddle/gserver/gradientmachines/MultiGradientMachine.h
+++ b/paddle/gserver/gradientmachines/MultiGradientMachine.h
@@ -189,7 +189,7 @@ public:
                        PassType passType,
                        const UpdateCallback& callback);
 
-  virtual const Argument& getLayerOutput(const std::string& layerName);
+  virtual Argument getLayerOutput(const std::string& layerName);
 
   virtual void onPassEnd();
 
diff --git a/paddle/gserver/gradientmachines/NeuralNetwork.cpp b/paddle/gserver/gradientmachines/NeuralNetwork.cpp
index d1afde40e1f81eea6b34c1e2c33fe4851d0074d6..2f2aa24aaca33a0c361a81025d6dca564e3672a1 100644
--- a/paddle/gserver/gradientmachines/NeuralNetwork.cpp
+++ b/paddle/gserver/gradientmachines/NeuralNetwork.cpp
@@ -293,7 +293,7 @@ void NeuralNetwork::backward(const UpdateCallback& callback) {
   }
 }
 
-const Argument& NeuralNetwork::getLayerOutput(const std::string& layerName) {
+Argument NeuralNetwork::getLayerOutput(const std::string& layerName) {
   return getLayer(layerName)->getOutput();
 }
 
diff --git a/paddle/gserver/gradientmachines/NeuralNetwork.h b/paddle/gserver/gradientmachines/NeuralNetwork.h
index b4dc38e31b6fae1dd721b4ec1f5cdd2e5fe50e61..e7b6c438407e7eab6eab1f6ed496f35caa9f2177 100644
--- a/paddle/gserver/gradientmachines/NeuralNetwork.h
+++ b/paddle/gserver/gradientmachines/NeuralNetwork.h
@@ -87,7 +87,7 @@ public:
 
   virtual void backward(const UpdateCallback& callback = nullptr);
 
-  virtual const Argument& getLayerOutput(const std::string& layerName);
+  virtual Argument getLayerOutput(const std::string& layerName);
 
   const LayerPtr& getLayer(const std::string& layerName) const {
     auto it = layerMap_.find(layerName);
diff --git a/paddle/gserver/layers/CosSimVecMatLayer.cpp b/paddle/gserver/layers/CosSimVecMatLayer.cpp
index aabafd473aa1e06a767d48d4c49b7b8662e992e7..0f887d8adfa053e8fe88ac4fa4e2a9ba08ac07b5 100644
--- a/paddle/gserver/layers/CosSimVecMatLayer.cpp
+++ b/paddle/gserver/layers/CosSimVecMatLayer.cpp
@@ -112,7 +112,7 @@ bool CosSimVecMatLayer::init(const LayerMap& layerMap,
 
 void CosSimVecMatLayer::forward(PassType passType) {
   Layer::forward(passType);
-  CHECK_EQ(forward_.size(), 1) << "Only one forward function needed";
+  CHECK_EQ(forward_.size(), 1UL) << "Only one forward function needed";
 
   MatrixPtr inV0 = getInputValue(0);
   MatrixPtr inV1 = getInputValue(1);
@@ -145,7 +145,7 @@ void CosSimVecMatLayer::forward(PassType passType) {
 }
 
 void CosSimVecMatLayer::backward(const UpdateCallback& callback) {
-  CHECK_EQ(backward_.size(), 1) << "Only one forward function needed";
+  CHECK_EQ(backward_.size(), 1UL) << "Only one forward function needed";
 
   MatrixPtr inV0 = getInputValue(0);
   MatrixPtr inV1 = getInputValue(1);