diff --git a/cocoscreator_projects/scripts/test/ui-frames.test.mjs b/cocoscreator_projects/scripts/test/ui-frames.test.mjs
index 5801dd6..515862d 100644
--- a/cocoscreator_projects/scripts/test/ui-frames.test.mjs
+++ b/cocoscreator_projects/scripts/test/ui-frames.test.mjs
@@ -44,6 +44,16 @@ test('frameRect 越界抛 RangeError 且带图名', () => {
   assert.throws(() => frameRect(IMG_00014, 13), /00014\.png/);
 });
 
+test('frameRect undefined 作为 frameIndex 抛 RangeError', () => {
+  assert.throws(() => frameRect(IMG_00014, undefined), RangeError);
+  assert.throws(() => frameRect(IMG_00014, undefined), /00014\.png/);
+});
+
+test('frameRect NaN 作为 frameIndex 抛 RangeError', () => {
+  assert.throws(() => frameRect(IMG_00014, NaN), RangeError);
+  assert.throws(() => frameRect(IMG_00014, NaN), /00014\.png/);
+});
+
 test('padWidth 按帧总数决定补零位数', () => {
   assert.equal(padWidth(9), 1);
   assert.equal(padWidth(12), 2);
@@ -61,6 +71,14 @@ test('frameFileName 单帧图原样返回', () => {
   assert.equal(frameFileName('00001.png', 1, 1), '00001.png');
 });
 
+test('frameFileName undefined 作为 frameIndex 抛 RangeError', () => {
+  assert.throws(() => frameFileName('00014.png', undefined, 12), RangeError);
+});
+
+test('frameFileName NaN 作为 frameIndex 抛 RangeError', () => {
+  assert.throws(() => frameFileName('00014.png', NaN, 12), RangeError);
+});
+
 test('frameNames 返回全部帧，下标 0 对应帧 1', () => {
   const names = frameNames(IMG_00014);
   assert.equal(names.length, 12);
diff --git a/cocoscreator_projects/scripts/ui-migration/frames.mjs b/cocoscreator_projects/scripts/ui-migration/frames.mjs
index 2dc113a..acf0a84 100644
--- a/cocoscreator_projects/scripts/ui-migration/frames.mjs
+++ b/cocoscreator_projects/scripts/ui-migration/frames.mjs
@@ -5,10 +5,11 @@
 
 /** 帧号 → 源矩形。FrameIndex=0 按帧 1 处理（实测仅 2 个对象如此）。 */
 export function frameRect(image, frameIndex) {
-  const idx = (frameIndex || 1) - 1;
-  if (idx < 0 || idx >= image.frame_all) {
+  const normalized = frameIndex === 0 ? 1 : frameIndex;
+  const idx = normalized - 1;
+  if (!Number.isInteger(idx) || idx < 0 || idx >= image.frame_all) {
     throw new RangeError(
-      `帧号越界: ${image.bmp} frameIndex=${frameIndex}（有效范围 1..${image.frame_all}）`,
+      `帧号非法或越界: ${image.bmp} frameIndex=${frameIndex}（有效范围 1..${image.frame_all}，0 视同 1）`,
     );
   }
   return {
@@ -27,8 +28,14 @@ export function padWidth(frameCount) {
 /** 00014.png + 帧 5/共 12 → 00014_05.png；单帧图原样返回。 */
 export function frameFileName(bmp, frameIndex, frameCount) {
   if (frameCount <= 1) return bmp;
+  const normalized = frameIndex === 0 ? 1 : frameIndex;
+  if (!Number.isInteger(normalized) || normalized <= 0) {
+    throw new RangeError(
+      `帧号非法: ${bmp} frameIndex=${frameIndex}（有效范围 >= 1，0 视同 1）`,
+    );
+  }
   const base = bmp.replace(/\.png$/i, '');
-  const n = String(frameIndex || 1).padStart(padWidth(frameCount), '0');
+  const n = String(normalized).padStart(padWidth(frameCount), '0');
   return `${base}_${n}.png`;
 }