diff --git a/paddle/fluid/inference/tensorrt/convert/ut_helper.h b/paddle/fluid/inference/tensorrt/convert/ut_helper.h
index bf740d38f0fa3e24b0824c4b69da2e1c7d9ab041..833f35167b91cecb2ab7e06c52b920d79d1cec0b 100644
--- a/paddle/fluid/inference/tensorrt/convert/ut_helper.h
+++ b/paddle/fluid/inference/tensorrt/convert/ut_helper.h
@@ -177,6 +177,9 @@ class TRTConvertValidation {
     ASSERT_FALSE(op_desc_->OutputArgumentNames().empty());
     const size_t output_space_size = 3000;
     for (const auto& output : op_desc_->OutputArgumentNames()) {
+      // Some Ops like batch norm, the output specified
+      // in the op des is only used during training, so we should
+      // neglect those ouput during inference.
       if (neglected_output.count(output)) continue;
       std::vector<float> fluid_out;
       std::vector<float> trt_out(output_space_size);