diff --git a/paddle/phi/kernels/gpu/grid_sample_grad_kernel.cu b/paddle/phi/kernels/gpu/grid_sample_grad_kernel.cu
index 6e8b12c4b1b900..2b6ceff59afa7f 100644
--- a/paddle/phi/kernels/gpu/grid_sample_grad_kernel.cu
+++ b/paddle/phi/kernels/gpu/grid_sample_grad_kernel.cu
@@ -121,16 +121,13 @@ ComputePositionsWithMask(T coord,
     coord = ClipIndexesWithMask(coord, size, &grad_clip);
     *grad_in = (*grad_in) * grad_clip;
   } else if (padding_mode == PaddingMode::reflect) {
-    if (align_corners) {
-      coord = ReflectIndexesWithMask(coord, 0, 2 * (size - 1), &grad_refl);
-    } else {
-      coord = ReflectIndexesWithMask(coord, -1, 2 * size - 1, &grad_refl);
-    }
+    coord = align_corners
+                ? ReflectIndexesWithMask(coord, 0, 2 * (size - 1), &grad_refl)
+                : ReflectIndexesWithMask(coord, -1, 2 * size - 1, &grad_refl);
     coord = ClipIndexesWithMask(coord, size, &grad_clip);
     *grad_in = (*grad_in) * grad_refl * grad_clip;
   }
-
-  return coord;
+  return SafeDownGradeToIntRange(coord);
 }
 
 template <typename T>
diff --git a/paddle/phi/kernels/gpu/grid_sample_kernel.cu b/paddle/phi/kernels/gpu/grid_sample_kernel.cu
index 3809ae7d5c3388..8499e371d10cf0 100644
--- a/paddle/phi/kernels/gpu/grid_sample_kernel.cu
+++ b/paddle/phi/kernels/gpu/grid_sample_kernel.cu
@@ -27,16 +27,13 @@ template <typename T>
 static __forceinline__ __device__ T Unnormalize(T coord,
                                                 int size,
                                                 bool align_corners) {
-  if (align_corners) {
-    return ((coord + 1.f) / 2) * (size - 1);
-  } else {
-    return ((coord + 1.f) * size - 1) / 2;
-  }
+  return align_corners ? ((coord + 1.f) / 2) * (size - 1)
+                       : ((coord + 1.f) * size - 1) / 2;
 }
 
 template <typename T>
 static __forceinline__ __device__ T ClipIndexes(T in, int max_value) {
-  return min(static_cast<T>(max_value), max(in, static_cast<T>(0)));
+  return min(static_cast<T>(max_value - 1), max(in, static_cast<T>(0)));
 }
 
 template <typename T>
@@ -51,11 +48,7 @@ static __forceinline__ __device__ T ReflectIndexes(T in,
   in = fabs(in - min);
   T extra = fmod(in, span);
   int flips = static_cast<int>(floor(in / span));
-  if (flips % 2 == 0) {
-    return extra + min;
-  } else {
-    return span - extra + min;
-  }
+  return (flips & 1) ? span - extra + min : extra + min;  // cond ? odd : even
 }
 
 template <typename T>
@@ -65,16 +58,13 @@ static __forceinline__ __device__ T ComputePositions(T coord,
                                                      bool align_corners) {
   coord = Unnormalize<T>(coord, size, align_corners);
   if (padding_mode == PaddingMode::border) {
-    coord = ClipIndexes(coord, size - 1);
+    coord = ClipIndexes(coord, size);
   } else if (padding_mode == PaddingMode::reflect) {
-    if (align_corners) {
-      coord = ReflectIndexes(coord, 0, 2 * (size - 1));
-    } else {
-      coord = ReflectIndexes(coord, -1, 2 * size - 1);
-    }
-    coord = ClipIndexes(coord, size - 1);
+    coord = align_corners ? ReflectIndexes(coord, 0, 2 * (size - 1))
+                          : ReflectIndexes(coord, -1, 2 * size - 1);
+    coord = ClipIndexes(coord, size);
   }
-  return coord;
+  return SafeDownGradeToIntRange(coord);
 }
 
 template <typename T>
diff --git a/paddle/phi/kernels/gpu/grid_sample_utils.h b/paddle/phi/kernels/gpu/grid_sample_utils.h
index bd5e859a59d1d2..415305efaa1057 100644
--- a/paddle/phi/kernels/gpu/grid_sample_utils.h
+++ b/paddle/phi/kernels/gpu/grid_sample_utils.h
@@ -14,6 +14,8 @@
 
 #pragma once
 
+#include <limits.h>
+
 namespace phi {
 
 enum class Mode {
@@ -21,6 +23,13 @@ enum class Mode {
   nearest,
 };
 
+template <typename T>
+__forceinline__ __device__ T SafeDownGradeToIntRange(T x) {
+  bool unsafe_cond =
+      x > INT_MAX - 1 || x < INT_MIN || !::isfinite(static_cast<double>(x));
+  return unsafe_cond ? static_cast<T>(-100.0) : x;
+}
+
 enum class PaddingMode { zeros, border, reflect };
 
 static __forceinline__ __device__ bool InBounds(int h, int w, int H, int W) {