diff --git a/setup.py b/setup.py
index 5a7afe86f7..95d551bfc8 100644
--- a/setup.py
+++ b/setup.py
@@ -368,7 +368,7 @@ def get_mluops_version(file_path):
                         exit()
 
             define_macros += [('MMCV_WITH_MLU', None)]
-            mlu_args = os.getenv('MMCV_MLU_ARGS')
+            mlu_args = os.getenv('MMCV_MLU_ARGS', '-DNDEBUG ')
             mluops_includes = []
             mluops_includes.append('-I' +
                                    os.path.abspath('./mlu-ops/bangc-ops'))