diff --git a/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.cc b/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.cc
index 1160ba57b7..0d49846bf7 100644
--- a/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.cc
+++ b/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.cc
@@ -179,8 +179,8 @@ bool MPIAdapter::ReduceScatter(const float *input, float *output, const std::vec
   return result;
 }
 
-bool MPIAdapter::ReduceScatterOverwriteInput(float *input, const std::vector<int> &ranks_group, size_t data_num,
-                                             const std::string &op_type, float *output) {
+bool MPIAdapter::ReduceScatterOverwriteInput(float *input, const std::vector<int> &ranks_group, size_t input_data_num,
+                                             size_t output_size, const std::string &op_type, float *output) {
   int scatter_index = GetScatterIndex(rank_id_, ranks_group);
   auto group = AddGroup(ranks_group);
   if (group == MPI_GROUP_NULL) {
@@ -193,7 +193,7 @@ bool MPIAdapter::ReduceScatterOverwriteInput(float *input, const std::vector<int
   }
 
   MPI_Win window;
-  auto ret = MPI_Win_create(input, data_num * sizeof(float), sizeof(float), MPI_INFO_NULL, comm, &window);
+  auto ret = MPI_Win_create(input, input_data_num * sizeof(float), sizeof(float), MPI_INFO_NULL, comm, &window);
   if (ret != MPI_SUCCESS) {
     MS_LOG(ERROR) << "mpi window create fail! ret = " << ret;
     return false;
@@ -205,18 +205,21 @@ bool MPIAdapter::ReduceScatterOverwriteInput(float *input, const std::vector<int
       continue;
     }
     auto op = GetMpiOp(op_type);
-    ret = MPI_Accumulate(input + i * data_num, data_num, MPI_FLOAT, remote_rank, i * data_num, data_num, MPI_FLOAT, op,
-                         window);
+    ret = MPI_Accumulate(input + i * input_data_num, input_data_num, MPI_FLOAT, remote_rank, i * input_data_num,
+                         input_data_num, MPI_FLOAT, op, window);
     if (ret != MPI_SUCCESS) {
       MS_LOG(EXCEPTION) << "mpi accumulate " << op_type << " fail!ret = " << ret;
     }
   }
   MPI_Win_fence(0, window);
   if (output != nullptr) {
-    auto data_size = data_num * sizeof(float);
-    auto copy_ret = memcpy_s(output, data_size, input + scatter_index * data_num, data_size);
+    auto data_size = input_data_num * sizeof(float);
+    if (output_size < data_size) {
+      MS_LOG(EXCEPTION) << "output buffer size " << output_size << " < input size " << data_size;
+    }
+    auto copy_ret = memcpy_s(output, output_size, input + scatter_index * input_data_num, data_size);
     if (copy_ret != 0) {
-      MS_LOG(EXCEPTION) << "copy output memory fail!";
+      MS_LOG(EXCEPTION) << "copy output memory fail!ret = " << copy_ret;
     }
   }
   MPI_Win_free(&window);
@@ -224,7 +227,7 @@ bool MPIAdapter::ReduceScatterOverwriteInput(float *input, const std::vector<int
   return true;
 }
 
-bool MPIAdapter::AllGather(float *input, float *output, const std::vector<int> &ranks_group, size_t data_num) {
+bool MPIAdapter::AllGather(const float *input, float *output, const std::vector<int> &ranks_group, size_t data_num) {
   if (ranks_group.empty()) {
     MS_LOG(ERROR) << "input rank group is empty!";
     return false;
diff --git a/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.h b/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.h
index 398ea1a364..8265e89eab 100644
--- a/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.h
+++ b/mindspore/ccsrc/device/cpu/mpi/mpi_adapter.h
@@ -34,9 +34,10 @@ class MPIAdapter {
   int GetRankId() const;
   bool ReduceScatter(const float *input, float *output, const std::vector<int> &ranks_group, size_t data_num,
                      const std::string &op_type = kOpTypeSum);
-  bool ReduceScatterOverwriteInput(float *input, const std::vector<int> &ranks_group, size_t data_num,
-                                   const std::string &op_type = kOpTypeSum, float *output = nullptr);
-  bool AllGather(float *input, float *output, const std::vector<int> &ranks_group, size_t data_num);
+  bool ReduceScatterOverwriteInput(float *input, const std::vector<int> &ranks_group, size_t input_data_num,
+                                   size_t output_size, const std::string &op_type = kOpTypeSum,
+                                   float *output = nullptr);
+  bool AllGather(const float *input, float *output, const std::vector<int> &ranks_group, size_t data_num);
 
  private:
   MPIAdapter();
diff --git a/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.cc b/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.cc
index 043fb7a0df..abb0c65d27 100644
--- a/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.cc
+++ b/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.cc
@@ -26,21 +26,11 @@ constexpr auto kRanksGroup = "group";
 constexpr auto kAllGatherInputNum = 1;
 }  // namespace
 
-AllGatherCPUKernel::AllGatherCPUKernel() : input_data_number_(0) {}
-
 void AllGatherCPUKernel::InitKernel(const CNodePtr &kernel_node) {
   size_t input_num = AnfAlgo::GetInputTensorNum(kernel_node);
   if (input_num != kAllGatherInputNum) {
     MS_LOG(EXCEPTION) << "allgather input num:" << input_num;
   }
-  for (size_t i = 0; i < input_num; ++i) {
-    auto shape = AnfAlgo::GetPrevNodeOutputInferShape(kernel_node, i);
-    size_t count = 1;
-    for (size_t j = 0; j < shape.size(); j++) {
-      count *= IntToSize(shape[j]);
-    }
-    input_data_number_ += count;
-  }
 
   auto ranks_group = AnfAlgo::GetCNodePrimitive(kernel_node)->GetAttr(kRanksGroup);
   if (ranks_group != nullptr) {
@@ -55,8 +45,9 @@ bool AllGatherCPUKernel::Launch(const std::vector<kernel::AddressPtr> &inputs,
                                 const std::vector<kernel::AddressPtr> &outputs) {
   auto input_addr = reinterpret_cast<float *>(inputs[0]->addr);
   auto output_addr = reinterpret_cast<float *>(outputs[0]->addr);
+  auto input_data_num = inputs[0]->size / sizeof(float);
 
-  return device::cpu::MPIAdapter::Instance().AllGather(input_addr, output_addr, ranks_group_, input_data_number_);
+  return device::cpu::MPIAdapter::Instance().AllGather(input_addr, output_addr, ranks_group_, input_data_num);
 }
 }  // namespace kernel
 }  // namespace mindspore
diff --git a/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.h b/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.h
index 6c06d3e851..94180fa89b 100644
--- a/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.h
+++ b/mindspore/ccsrc/kernel/cpu/allgather_cpu_kernel.h
@@ -24,7 +24,7 @@ namespace mindspore {
 namespace kernel {
 class AllGatherCPUKernel : public CPUKernel {
  public:
-  AllGatherCPUKernel();
+  AllGatherCPUKernel() = default;
   ~AllGatherCPUKernel() override = default;
 
   void InitKernel(const CNodePtr &kernel_node) override;
@@ -33,7 +33,6 @@ class AllGatherCPUKernel : public CPUKernel {
               const std::vector<AddressPtr> &outputs) override;
 
  private:
-  size_t input_data_number_;
   std::vector<int> ranks_group_;
 };
 
diff --git a/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.cc b/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.cc
index 69cea98a47..fd8a74eb6b 100644
--- a/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.cc
+++ b/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.cc
@@ -24,18 +24,9 @@ namespace {
 constexpr auto kRanksGroup = "group";
 }  // namespace
 
-ReduceScatterCPUKernel::ReduceScatterCPUKernel() : output_data_number_(0), op_type_(device::cpu::kOpTypeSum) {}
+ReduceScatterCPUKernel::ReduceScatterCPUKernel() : op_type_(device::cpu::kOpTypeSum) {}
 
 void ReduceScatterCPUKernel::InitKernel(const CNodePtr &kernel_node) {
-  size_t output_num = AnfAlgo::GetOutputTensorNum(kernel_node);
-  for (size_t i = 0; i < output_num; ++i) {
-    auto shape = AnfAlgo::GetOutputInferShape(kernel_node, i);
-    size_t size = 1;
-    for (size_t j = 0; j < shape.size(); j++) {
-      size *= IntToSize(shape[j]);
-    }
-    output_data_number_ += size;
-  }
   auto op = AnfAlgo::GetCNodePrimitive(kernel_node)->GetAttr("op");
   if (op != nullptr) {
     op_type_ = GetValue<std::string>(op);
@@ -54,8 +45,9 @@ bool ReduceScatterCPUKernel::Launch(const std::vector<kernel::AddressPtr> &input
                                     const std::vector<kernel::AddressPtr> &outputs) {
   auto input_addr = reinterpret_cast<float *>(inputs[0]->addr);
   auto output_addr = reinterpret_cast<float *>(outputs[0]->addr);
+  auto output_data_num = outputs[0]->size / sizeof(float);
 
-  return device::cpu::MPIAdapter::Instance().ReduceScatter(input_addr, output_addr, ranks_group_, output_data_number_,
+  return device::cpu::MPIAdapter::Instance().ReduceScatter(input_addr, output_addr, ranks_group_, output_data_num,
                                                            op_type_);
 }
 }  // namespace kernel
diff --git a/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.h b/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.h
index cebf649954..c3bfe571a4 100644
--- a/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.h
+++ b/mindspore/ccsrc/kernel/cpu/reduce_scatter_cpu_kernel.h
@@ -33,7 +33,6 @@ class ReduceScatterCPUKernel : public CPUKernel {
               const std::vector<AddressPtr> &outputs) override;
 
  private:
-  size_t output_data_number_;
   std::string op_type_;
   std::vector<int> ranks_group_;
 };