diff --git a/paddle/framework/operator.cc b/paddle/framework/operator.cc
index e3c510b70346a2baf6ccd756eaf689c146efee5f..cfe9cba308556475ef64b45e7178dfc418761598 100644
--- a/paddle/framework/operator.cc
+++ b/paddle/framework/operator.cc
@@ -52,7 +52,8 @@ std::vector<std::string> OperatorBase::Inputs(const std::string& name) const {
   PADDLE_ENFORCE(in_out_idxs_ != nullptr, "IO Idx could not be nullptr");
   auto input_format = GetAttr<std::vector<int>>("input_format");
   auto offset = in_out_idxs_->at(name);
-  PADDLE_ENFORCE(input_format.at((size_t)offset + 1) <= (int)inputs_.size(),
+  PADDLE_ENFORCE(input_format.at(static_cast<size_t>(offset) + 1) <=
+                     static_cast<int>(inputs_.size()),
                  "Input Out Of Range");
 
   return std::vector<std::string>{
@@ -78,7 +79,8 @@ std::vector<std::string> OperatorBase::Outputs(const std::string& name) const {
   PADDLE_ENFORCE(in_out_idxs_ != nullptr, "InOut Indice could not be nullptr");
   auto output_format = GetAttr<std::vector<int>>("output_format");
   auto offset = in_out_idxs_->at(name);
-  PADDLE_ENFORCE(output_format.at((size_t)offset + 1) <= (int)outputs_.size(),
+  PADDLE_ENFORCE(output_format.at(static_cast<size_t>(offset) + 1) <=
+                     static_cast<int>(outputs_.size()),
                  "Output Out of Range");
   return std::vector<std::string>{
       outputs_.begin() + output_format.at(offset),
diff --git a/paddle/framework/operator.h b/paddle/framework/operator.h
index 6a9fe19b9b61333cf9db1cca3e34c72f3f9c99c5..0832a663dd01fe2921366d70599bc867e73af47c 100644
--- a/paddle/framework/operator.h
+++ b/paddle/framework/operator.h
@@ -161,22 +161,30 @@ class OperatorContext {
 
   template <typename T>
   const T* Input(const size_t index) const {
-    return &(InputVar(index)->Get<T>());
+    auto var = InputVar(index);
+    PADDLE_ENFORCE(var != nullptr, "Input(%d) should not be nullptr", index);
+    return &var->Get<T>();
   }
 
   template <typename T>
   T* Output(const size_t index) const {
-    return OutputVar(index)->GetMutable<T>();
+    auto var = OutputVar(index);
+    PADDLE_ENFORCE(var != nullptr, "Output(%d) should not be nullptr", index);
+    return var->GetMutable<T>();
   }
 
   template <typename T>
   const T* Input(const std::string& name) const {
-    return &(InputVar(name)->Get<T>());
+    auto var = InputVar(name);
+    PADDLE_ENFORCE(var != nullptr, "Input(%s) should not be nullptr", name);
+    return &var->Get<T>();
   }
 
   template <typename T>
   T* Output(const std::string& name) const {
-    return OutputVar(name)->GetMutable<T>();
+    auto var = OutputVar(name);
+    PADDLE_ENFORCE(var != nullptr, "Output(%s) should not be nullptr", name);
+    return var->GetMutable<T>();
   }
 
   template <typename T>
@@ -185,8 +193,12 @@ class OperatorContext {
     std::vector<const T*> res;
     res.reserve(names.size());
     std::transform(names.begin(), names.end(), std::back_inserter(res),
-                   [this](const std::string& name) {
-                     return &scope_.FindVar(name)->Get<T>();
+                   [&](const std::string& sub_name) {
+                     auto var = scope_.FindVar(sub_name);
+                     PADDLE_ENFORCE(var != nullptr,
+                                    "MultiInput(%s:%s) should not be nullptr",
+                                    name, sub_name);
+                     return &var->Get<T>();
                    });
     return res;
   }
@@ -197,8 +209,12 @@ class OperatorContext {
     std::vector<const T*> res;
     res.reserve(names.size());
     std::transform(names.begin(), names.end(), std::back_inserter(res),
-                   [this](const std::string& name) {
-                     return scope_.FindVar(name)->GetMutable<T>();
+                   [&](const std::string& sub_name) {
+                     auto var = scope_.FindVar(sub_name);
+                     PADDLE_ENFORCE(var != nullptr,
+                                    "MultiOutput(%s:%s) should not be nullptr",
+                                    name, sub_name);
+                     return var->GetMutable<T>();
                    });
     return res;
   }