diff --git a/paddle/fluid/operators/activation_op.h b/paddle/fluid/operators/activation_op.h
index 1839c7e9bce3c7013b8c0ab49e6d7bee5e881795..292505ae6c3b30ad49f868a11c0482707242a251 100644
--- a/paddle/fluid/operators/activation_op.h
+++ b/paddle/fluid/operators/activation_op.h
@@ -477,7 +477,7 @@ struct RsqrtGradFunctor : public BaseActivationFunctor<T> {
   template <typename Device, typename X, typename Out, typename dOut,
             typename dX>
   void operator()(Device d, X x, Out out, dOut dout, dX dx) const {
-    dx.device(d) = static_cast<T>(-0.5) * dout * out.pow(3);
+    dx.device(d) = static_cast<T>(-0.5) * dout * out * out * out;
   }
 };