diff --git a/mmpretrain/datasets/transforms/auto_augment.py b/mmpretrain/datasets/transforms/auto_augment.py
index 03b057b850a..4705d5ec04e 100644
--- a/mmpretrain/datasets/transforms/auto_augment.py
+++ b/mmpretrain/datasets/transforms/auto_augment.py
@@ -1169,7 +1169,7 @@ def transform(self, results):
 
         img = results['img']
         pil_img = Image.fromarray(img)
-        pil_img.filter(ImageFilter.GaussianBlur(radius=radius))
+        pil_img = pil_img.filter(ImageFilter.GaussianBlur(radius=radius))
         results['img'] = np.array(pil_img, dtype=img.dtype)
 
         return results
diff --git a/tests/test_datasets/test_transforms/test_auto_augment.py b/tests/test_datasets/test_transforms/test_auto_augment.py
index fa0761016f4..d9f65c3d993 100644
--- a/tests/test_datasets/test_transforms/test_auto_augment.py
+++ b/tests/test_datasets/test_transforms/test_auto_augment.py
@@ -1285,9 +1285,10 @@ def test_initialize(self):
 
     def test_transform(self):
         transform_func = 'PIL.ImageFilter.GaussianBlur'
+        from PIL.ImageFilter import GaussianBlur
 
         # test params inputs
-        with patch(transform_func, autospec=True) as mock:
+        with patch(transform_func, wraps=GaussianBlur) as mock:
             cfg = {
                 **self.DEFAULT_ARGS,
                 'radius': 0.5,
@@ -1297,7 +1298,7 @@ def test_transform(self):
             mock.assert_called_once_with(radius=0.5)
 
         # test prob
-        with patch(transform_func, autospec=True) as mock:
+        with patch(transform_func, wraps=GaussianBlur) as mock:
             cfg = {
                 **self.DEFAULT_ARGS,
                 'radius': 0.5,
@@ -1307,7 +1308,7 @@ def test_transform(self):
             mock.assert_not_called()
 
         # test magnitude_range
-        with patch(transform_func, autospec=True) as mock:
+        with patch(transform_func, wraps=GaussianBlur) as mock:
             cfg = {
                 **self.DEFAULT_ARGS,
                 'magnitude_range': (0.1, 2),