diff --git a/mindspore/ccsrc/device/ascend/kernel_select_ascend.cc b/mindspore/ccsrc/device/ascend/kernel_select_ascend.cc
index df19e7708a..4fadb4f37b 100644
--- a/mindspore/ccsrc/device/ascend/kernel_select_ascend.cc
+++ b/mindspore/ccsrc/device/ascend/kernel_select_ascend.cc
@@ -23,9 +23,7 @@
 #include "kernel/oplib/oplib.h"
 #include "kernel/kernel_query.h"
 #include "session/anf_runtime_algorithm.h"
-#include "kernel/kernel_build_info.h"
 #include "utils/context/ms_context.h"
-#include "operator/ops.h"
 #include "debug/anf_ir_dump.h"
 
 namespace mindspore {
@@ -45,7 +43,6 @@ enum MatchCountPriority : int {
   MATCH_COUNT_PRIORITY_END
 };
 
-const size_t kMaxCount = 0xffffffff;
 const int kUnSupportMixedDataTypeIndex = -1;
 
 bool MatchInferOutputDataType(const CNodePtr &cnode, const kernel::KernelBuildInfo &kernel_build_info) {
@@ -91,7 +88,7 @@ string GetPriorityMatchFormat(const CNodePtr &cnode) {
   return priority_matched_format;
 }
 /**
- * compare two vector by priority, select a better vector, like compare two num, first compare highest num location,
+ * Compare two vector by priority, select a better vector, like compare two num, first compare highest num location,
  * if equal then next num location
  * example:[3,1,1,1] > [2,2,2,2] > [2,2,1,2] > [2,1,1,3]
  */
@@ -167,8 +164,9 @@ void SetTensorDeviceInfo(const kernel::KernelBuildInfo &selected_kernel_info, co
     if (op_info != nullptr) {
       is_ref = op_info->is_ref();
     }
-    MS_EXCEPTION_IF_NULL(MsContext::GetInstance());
-    if (MsContext::GetInstance()->execution_mode() == kPynativeMode &&
+    auto ms_context = MsContext::GetInstance();
+    MS_EXCEPTION_IF_NULL(ms_context);
+    if (ms_context->execution_mode() == kPynativeMode &&
         AnfAlgo::GetOutputDeviceDataType(real_input_node, 0) != kTypeUnknown) {
       continue;
     }
@@ -221,6 +219,7 @@ void AddNodeInputDataType(const CNodePtr &kernel_node, size_t input_index,
                           std::vector<TypeId> *node_mix_precision_datatype) {
   AnfNodePtr cur_input = AnfAlgo::GetInputNode(kernel_node, input_index);
   MS_EXCEPTION_IF_NULL(cur_input);
+  MS_EXCEPTION_IF_NULL(node_mix_precision_datatype);
   TypeId input_origin_type = AnfAlgo::GetPrevNodeOutputInferDataType(kernel_node, input_index);
   AddSupportMixedPrecisionDataTypeIndex(input_origin_type, node_mix_precision_datatype_index);
   node_mix_precision_datatype->push_back(input_origin_type);
@@ -229,6 +228,7 @@ void AddNodeInputDataType(const CNodePtr &kernel_node, size_t input_index,
 void AddNodeOutputDataType(const CNodePtr &kernel_node, size_t output_index,
                            std::vector<int> *node_mix_precision_datatype_index,
                            std::vector<TypeId> *node_mix_precision_datatype) {
+  MS_EXCEPTION_IF_NULL(node_mix_precision_datatype);
   auto output_origin_type = AnfAlgo::GetOutputInferDataType(kernel_node, output_index);
   AddSupportMixedPrecisionDataTypeIndex(output_origin_type, node_mix_precision_datatype_index);
   node_mix_precision_datatype->push_back(output_origin_type);
@@ -239,12 +239,12 @@ void CheckDataTypeInputs(const std::vector<int> &node_mix_precision_datatype_ind
                          const std::map<size_t, std::vector<TypeId>> &kernel_support_datatypes,
                          std::map<size_t, std::vector<int>> *kernel_match_datatype_idx) {
   if (node_mix_precision_datatype_index.size() != node_mix_precision_datatype.size()) {
-    MS_LOG(EXCEPTION) << "node datatype index size " << node_mix_precision_datatype_index.size() << " != datatype size "
+    MS_LOG(EXCEPTION) << "Node datatype index size " << node_mix_precision_datatype_index.size() << " != datatype size "
                       << node_mix_precision_datatype.size();
   }
   MS_EXCEPTION_IF_NULL(kernel_match_datatype_idx);
   if (kernel_support_datatypes.size() != kernel_match_datatype_idx->size()) {
-    MS_LOG(EXCEPTION) << "kernel datatype index size " << kernel_match_datatype_idx->size() << " != datatype size "
+    MS_LOG(EXCEPTION) << "Kernel datatype index size " << kernel_match_datatype_idx->size() << " != datatype size "
                       << kernel_support_datatypes.size();
   }
 }
@@ -265,10 +265,10 @@ bool RaiseDataTypePrecisionSelect(const std::vector<int> &node_mix_precision_dat
       if (node_mix_precision_datatype_index[i] == kUnSupportMixedDataTypeIndex) {
         auto find_iter = kernel_support_datatypes.find(iter->first);
         if (find_iter == kernel_support_datatypes.end()) {
-          MS_LOG(EXCEPTION) << "kernel datatype index:%lu can not be found " << iter->first;
+          MS_LOG(EXCEPTION) << "Kernel datatype index:%lu can not be found " << iter->first;
         }
         if (i >= find_iter->second.size()) {
-          MS_LOG(EXCEPTION) << "node index " << i << "kernel datatype size " << find_iter->second.size();
+          MS_LOG(EXCEPTION) << "Node index " << i << "kernel datatype size " << find_iter->second.size();
         }
         if (node_mix_precision_datatype[i] != find_iter->second[i]) {
           iter = kernel_match_datatype_idx->erase(iter);
@@ -279,7 +279,7 @@ bool RaiseDataTypePrecisionSelect(const std::vector<int> &node_mix_precision_dat
       }
       auto datatype_indexes = iter->second;
       if (i >= datatype_indexes.size()) {
-        MS_LOG(EXCEPTION) << "node datatype index: " << i << " kernel support size " << datatype_indexes.size();
+        MS_LOG(EXCEPTION) << "Node datatype index: " << i << " kernel support size " << datatype_indexes.size();
       }
       if (datatype_indexes[i] < node_mix_precision_datatype_index[i]) {
         iter = kernel_match_datatype_idx->erase(iter);
@@ -415,8 +415,8 @@ std::shared_ptr<kernel::KernelBuildInfo> ChooseMatchedKernelInfo(
   size_t selected_index = 0;
   for (size_t info_index = 0; info_index < kernel_info_list.size(); ++info_index) {
     std::vector<int> cur_kernel_info_match_counts = {0, 0, 0, 0, 0};
-    auto kernel_build_info = *(kernel_info_list[info_index]);
-    std::shared_ptr<kernel::KernelBuildInfo> kernel_info_ptr = kernel_info_list[info_index];
+    auto kernel_info_ptr = kernel_info_list[info_index];
+    MS_EXCEPTION_IF_NULL(kernel_info_ptr);
     UpdateCurMatchCounts(*kernel_info_ptr, kernel_node, &cur_kernel_info_match_counts);
     // Currently the selection policy is the match format count first, and then is datatype counts.
     if (PriorityChooseItem(cur_kernel_info_match_counts, &most_match_counts)) {