diff --git a/paddle/fluid/operators/detection/roi_perspective_transform_op.cc b/paddle/fluid/operators/detection/roi_perspective_transform_op.cc
index b98190d40a2afa684cfd29cc52fc29fac851cca7..4cc980b41b34894f9d915d4b325887548091c0eb 100644
--- a/paddle/fluid/operators/detection/roi_perspective_transform_op.cc
+++ b/paddle/fluid/operators/detection/roi_perspective_transform_op.cc
@@ -23,8 +23,6 @@ namespace operators {
 using Tensor = framework::Tensor;
 using LoDTensor = framework::LoDTensor;
 
-static constexpr int kROISize = 4;
-
 template <typename T>
 bool GT_E(T a, T b) {
   return (a > b) || fabs(a - b) < 1e-4;