diff --git a/paddle/fluid/inference/tensorrt/convert/ut_helper.h b/paddle/fluid/inference/tensorrt/convert/ut_helper.h
index bf740d38f0fa3e24b0824c4b69da2e1c7d9ab041..0a6f171fc40a838fd81d6a51aca0430d5526f188 100644
--- a/paddle/fluid/inference/tensorrt/convert/ut_helper.h
+++ b/paddle/fluid/inference/tensorrt/convert/ut_helper.h
@@ -163,6 +163,9 @@ class TRTConvertValidation {
     }
   }
 
+  // We use the set 'neglected_output' here, because some Ops like batch norm,
+  // the outputs specified in the op des are only used during training,
+  // so we should neglect those output during inference.
   void Execute(int batch_size,
                std::unordered_set<std::string> neglected_output = {}) {
     // Execute Fluid Op