diff --git a/mindspore/ccsrc/backend/kernel_compiler/gpu/cuda_impl/prelu_grad_impl.cu b/mindspore/ccsrc/backend/kernel_compiler/gpu/cuda_impl/prelu_grad_impl.cu
index 2b2cd7d5dbc..f151aea026d 100644
--- a/mindspore/ccsrc/backend/kernel_compiler/gpu/cuda_impl/prelu_grad_impl.cu
+++ b/mindspore/ccsrc/backend/kernel_compiler/gpu/cuda_impl/prelu_grad_impl.cu
@@ -22,11 +22,12 @@ template <typename T>
 __global__ void CalPReLUGradKernel(size_t size, size_t weight_size, size_t per_channel_size,
                                    const T *dy, const T *x, const T *w, T *dx, float *dw_array) {
   for (size_t pos = blockIdx.x * blockDim.x + threadIdx.x; pos < size; pos += blockDim.x * gridDim.x) {
+    size_t thread_id = blockIdx.x * blockDim.x + threadIdx.x;
     size_t channel_id = weight_size == 1 ? 0 : (pos / per_channel_size) % weight_size;
-    dx[pos] = pos[x] <= static_cast<T>(0) ? w[channel_id] * dy[pos] : dy[pos];
-
-    if (pos[x] < static_cast<T>(0)) {
-      size_t index = channel_id * blockDim.x * gridDim.x + pos;
+    size_t index = channel_id * blockDim.x * gridDim.x + thread_id;
+    T threshold = static_cast<T>(0);
+    dx[pos] = x[pos] <= threshold ? w[channel_id] * dy[pos] : dy[pos];
+    if (x[pos] < threshold) {
       dw_array[index] += static_cast<float>(x[pos] * dy[pos]);
     }
   }