diff --git a/src/layer/flip.cpp b/src/layer/flip.cpp
index 4cf4dcb9f46..ad8deac089a 100644
--- a/src/layer/flip.cpp
+++ b/src/layer/flip.cpp
@@ -179,11 +179,8 @@ int Flip::forward(const Mat& bottom_blob, Mat& top_blob, const Option& opt) cons
                     {
                         // 组合两种翻转：channel维度和行维度同时翻转
                         const float* ptr = bottom_blob.channel(channels - 1 - i).row(h - 1 - j);
-                        float* outptr = top_blob.channel(i).row(j);
-                        // memcpy(outptr, ptr, w * sizeof(float));
-                        // memcpy(outptr, ptr, w * elemsize);
-                        for (int x = 0; x < w; x++)
-                            outptr[x] = ptr[x];
+                        float* outptr = const_cast<float*>(top_blob.channel(i).row(j));
+                        memcpy(outptr, ptr, w * sizeof(float));
                     }
                 }
             }