diff --git a/paddle/fluid/operators/space_to_depth_op.cc b/paddle/fluid/operators/space_to_depth_op.cc
index f109dd685c87ab1b0776a855bb5f510eab1f5526..c047bc78ee315201d25a7294b7dae7d766a6c968 100644
--- a/paddle/fluid/operators/space_to_depth_op.cc
+++ b/paddle/fluid/operators/space_to_depth_op.cc
@@ -86,7 +86,7 @@ class SpaceToDepthOpMaker : public framework::OpProtoAndCheckerMaker {
         .GreaterThan(1);
     AddComment(R"DOC(
         reorg operator used in Yolo v2.
-        The equation is: C2 = C1/blocksize * blocksize, W2 = W1 ∗ blocksize + offset % blocksize, H2 = H1 ∗ blocksize + offset / blocksize, 
+        The equation is: C2 = C1/blocksize * blocksize, W2 = W1 * blocksize + offset % blocksize, H2 = H1 * blocksize + offset / blocksize,   
 
         Reshape Input(X) into the shape according to Attr(blocksize). The
         data in Input(X) are unchanged.