diff --git a/paddle/fluid/inference/tensorrt/convert/pool2d_op.cc b/paddle/fluid/inference/tensorrt/convert/pool2d_op.cc
index 768318fb063297031ae4cc1690e022624de021de..1d0d83d1f368f879878a4df8b2eefae0bc89423d 100644
--- a/paddle/fluid/inference/tensorrt/convert/pool2d_op.cc
+++ b/paddle/fluid/inference/tensorrt/convert/pool2d_op.cc
@@ -109,6 +109,10 @@ class Pool2dOpConverter : public OpConverter {
     }
 
     if (pool_type == "max") {
+      // Under ceil mode, the pre_pad and post_pad are used to
+      // record the the padding size. In some ceil mode cases,
+      // we do not need padding, so we initialize the two vars to 0.
+
       nvinfer1::DimsHW pre_pad(0, 0);
       nvinfer1::DimsHW post_pad(0, 0);
       if (ceil_mode) {