diff --git a/mmcls/models/classifiers/image.py b/mmcls/models/classifiers/image.py
index 043a9eb25..283d86a95 100644
--- a/mmcls/models/classifiers/image.py
+++ b/mmcls/models/classifiers/image.py
@@ -94,4 +94,7 @@ class ImageClassifier(BaseClassifier):
     def simple_test(self, img, img_metas):
         """Test without augmentation."""
         x = self.extract_feat(img)
+        x_dims = len(x.shape)
+        if x_dims == 1:
+            x.unsqueeze_(0)
         return self.head.simple_test(x)