diff --git a/mindspore/ccsrc/runtime/device/ascend/ascend_memory_manager.cc b/mindspore/ccsrc/runtime/device/ascend/ascend_memory_manager.cc
index c5ce0bf3a33..14f4e119fce 100644
--- a/mindspore/ccsrc/runtime/device/ascend/ascend_memory_manager.cc
+++ b/mindspore/ccsrc/runtime/device/ascend/ascend_memory_manager.cc
@@ -27,14 +27,29 @@ using mindspore::profiler::MemoryProfiling;
 namespace mindspore {
 namespace device {
 namespace ascend {
+namespace {
 constexpr uint64_t kAscendInitDeviceMemGB = 30;
 constexpr uint64_t kAscendMaxDeviceMemGB = 31;
 constexpr uint64_t kMemSizeGB = 30;
 constexpr uint64_t kAscendDeviceMemSize = (kAscendInitDeviceMemGB << kMemSizeGB);
 
+uint64_t GetDefaultDeviceMemSize() {
+  size_t free = 0;
+  size_t total = 0;
+  rtError_t ret = rtMemGetInfoEx(RT_MEMORYINFO_HBM, &free, &total);
+  if (ret != RT_ERROR_NONE || total == 0) {
+    MS_LOG(WARNING) << "Get total HBM memory size failed, ret = " << ret << ", use default value "
+                    << kAscendDeviceMemSize;
+    return kAscendDeviceMemSize;
+  }
+
+  return total * 15 / 16;  // reserved memory is 1/16 of total
+}
+}  // namespace
+
 void AscendMemoryManager::MallocDeviceMemory() {
   auto context_mem = GetDeviceMemSizeFromContext();
-  device_mem_size_ = context_mem == 0 ? kAscendDeviceMemSize : context_mem;
+  device_mem_size_ = context_mem == 0 ? GetDefaultDeviceMemSize() : context_mem;
   auto ret = rtMalloc(reinterpret_cast<void **>(&device_mem_base_), device_mem_size_, RT_MEMORY_HBM);
   if (ret != ACL_RT_SUCCESS) {
     if (ret == ACL_ERROR_RT_MEMORY_ALLOCATION) {
@@ -56,7 +71,7 @@ void AscendMemoryManager::MallocDeviceMemory() {
 
 uint64_t AscendMemoryManager::GetDeviceMemSize() {
   auto mem_size = GetDeviceMemSizeFromContext();
-  return mem_size == 0 ? kAscendDeviceMemSize : mem_size;
+  return mem_size == 0 ? GetDefaultDeviceMemSize() : mem_size;
 }
 
 uint64_t AscendMemoryManager::GetDeviceMemSizeFromContext() {
diff --git a/tests/ut/cpp/stub/runtime/runtime_stub.cc b/tests/ut/cpp/stub/runtime/runtime_stub.cc
index 8e7d749e58a..0682ce3e7f8 100644
--- a/tests/ut/cpp/stub/runtime/runtime_stub.cc
+++ b/tests/ut/cpp/stub/runtime/runtime_stub.cc
@@ -195,3 +195,5 @@ RTS_API rtError_t rtKernelLaunchWithFlag(const void *stubFunc, uint32_t blockDim
                                          rtSmDesc_t *smDesc, rtStream_t stream, uint32_t flags) {
   return RT_ERROR_NONE;
 }
+
+RTS_API rtError_t rtMemGetInfoEx(rtMemInfoType_t memInfoType, size_t *free, size_t *total) { return RT_ERROR_NONE; }