diff --git a/paddle/operators/recurrent_op.h b/paddle/operators/recurrent_op.h
index 35e6d9d50dd04048da7ffb384014d5909cd659a4..f859dc333d20ecf04fcb080e459391c8a0122bb1 100644
--- a/paddle/operators/recurrent_op.h
+++ b/paddle/operators/recurrent_op.h
@@ -19,8 +19,6 @@
 namespace paddle {
 namespace operators {
 
-using namespace paddle::framework;  // NOLINT
-
 namespace rnn {
 
 /**
diff --git a/paddle/platform/device_context.h b/paddle/platform/device_context.h
index 48b9f5dcb5cc578f9e70ed7abe076b66b68dc719..08b5b2cff900cc4239a615fe7d7f6b5faa13510b 100644
--- a/paddle/platform/device_context.h
+++ b/paddle/platform/device_context.h
@@ -55,7 +55,7 @@ class CPUDeviceContext : public DeviceContext {
 
 class CUDADeviceContext : public DeviceContext {
  public:
-  CUDADeviceContext(GPUPlace);  // NOLINT
+  explicit CUDADeviceContext(GPUPlace);
   virtual ~CUDADeviceContext();
 
   /*! \brief  Wait for all operations completion in the stream. */
diff --git a/paddle/platform/place.h b/paddle/platform/place.h
index a37ad38a8fb030192fa4c871106c6eb54816768a..a82e8c942fa28297d91056a66b61f085f2bdb946 100644
--- a/paddle/platform/place.h
+++ b/paddle/platform/place.h
@@ -32,7 +32,7 @@ struct CPUPlace {
 
 struct GPUPlace {
   GPUPlace() : GPUPlace(0) {}
-  GPUPlace(int d) : device(d) {}  // NOLINT
+  explicit GPUPlace(int d) : device(d) {}
 
   // needed for variant equality comparison
   inline bool operator==(const GPUPlace &o) const { return device == o.device; }
diff --git a/paddle/string/piece.h b/paddle/string/piece.h
index 3b887490b5c6c016bc30d8db060c5c1c01b8bf54..7deeacd8ca99da21a34913c67aa66ece0bd7d495 100644
--- a/paddle/string/piece.h
+++ b/paddle/string/piece.h
@@ -39,8 +39,8 @@ public:
   // size_ is 0.
   Piece();
   Piece(const char* d, size_t n);
-  Piece(const char* d);         // NOLINT
-  Piece(const std::string& s);  // NOLINT
+  explicit Piece(const char* d);
+  explicit Piece(const std::string& s);
 
   const char* data() const { return data_; }
   size_t len() const { return size_; }