diff --git a/paddle/operators/detection_output_op.h b/paddle/operators/detection_output_op.h
index cd6417087a027c394e896c73d5dc7f5bafac65e5..f8abd5b6406f05747b87fcfd464baeb705a7f7f2 100644
--- a/paddle/operators/detection_output_op.h
+++ b/paddle/operators/detection_output_op.h
@@ -63,7 +63,7 @@ class DetectionOutputKernel : public framework::OpKernel<T> {
     float nms_threshold = context.template Attr<float>("nms_threshold");
     float confidence_threshold =
         context.template Attr<float>("confidence_threshold");
-    int batch_size = in_conf->dims()[1];
+    size_t batch_size = in_conf->dims()[1];
     int conf_sum_size = in_conf->numel();
     // for softmax
     std::vector<int64_t> conf_shape_softmax_vec(