diff --git a/paddle/fluid/framework/op_kernel_type.h b/paddle/fluid/framework/op_kernel_type.h
index a2e9d972c48bc..8b1f0942f820a 100644
--- a/paddle/fluid/framework/op_kernel_type.h
+++ b/paddle/fluid/framework/op_kernel_type.h
@@ -82,9 +82,9 @@ class OpKernelType {
 
 inline std::ostream& operator<<(std::ostream& os,
                                 const OpKernelType& kernel_key) {
-  os << "data_type[" << kernel_key.data_type_ << "]:data_layout["
-     << kernel_key.data_layout_ << "]:place[" << kernel_key.place_
-     << "]:library_type[" << kernel_key.library_type_ << "]";
+  os << "{data_type[" << kernel_key.data_type_ << "]; data_layout["
+     << kernel_key.data_layout_ << "]; place[" << kernel_key.place_
+     << "]; library_type[" << kernel_key.library_type_ << "]}";
   return os;
 }
 
diff --git a/paddle/fluid/framework/op_kernel_type_test.cc b/paddle/fluid/framework/op_kernel_type_test.cc
index 3879a7957600d..20f695d40568e 100644
--- a/paddle/fluid/framework/op_kernel_type_test.cc
+++ b/paddle/fluid/framework/op_kernel_type_test.cc
@@ -27,16 +27,15 @@ TEST(OpKernelType, ToString) {
                               LibraryType::kCUDNN);
 
   ASSERT_EQ(paddle::framework::KernelTypeToString(op_kernel_type),
-            "data_type[float]:data_layout[NCHW]:place[Place(cpu)]:library_type["
-            "CUDNN]");
+            "{data_type[float]; data_layout[NCHW]; place[Place(cpu)]; "
+            "library_type[CUDNN]}");
 
   using CUDAPlace = paddle::platform::CUDAPlace;
   OpKernelType op_kernel_type2(DataType::FP16, CUDAPlace(0), DataLayout::kNCHW,
                                LibraryType::kCUDNN);
   ASSERT_EQ(paddle::framework::KernelTypeToString(op_kernel_type2),
-            "data_type[::paddle::platform::float16]:data_layout[NCHW]:place["
-            "Place(gpu:0)]:library_"
-            "type[CUDNN]");
+            "{data_type[::paddle::platform::float16]; data_layout[NCHW]; "
+            "place[Place(gpu:0)]; library_type[CUDNN]}");
 }
 
 TEST(OpKernelType, Hash) {