diff --git a/mmcv/ops/masked_conv.py b/mmcv/ops/masked_conv.py
index 82f16d4a39..f591b17088 100644
--- a/mmcv/ops/masked_conv.py
+++ b/mmcv/ops/masked_conv.py
@@ -52,13 +52,15 @@ def forward(ctx,
                 weight,
                 bias,
                 stride=(stride_h, stride_w),
-                padding=padding,
+                padding=(pad_h, pad_w),
                 dilation=(1, 1),
                 groups=1)
-            features_h, features_w = features.size()[2:]
-            mask_reshape = mask.reshape(1, 1, features_h, features_w)
-            mask_bool = mask_reshape > 0
-            output = conv * mask_bool
+            if mask.size()[1:] != conv.size()[2:]:
+                raise ValueError(
+                    'The mask is inconsistent with the shape of output_conv.')
+            conv_h, conv_w = conv.size()[2:]
+            mask_reshape = mask.reshape(1, 1, conv_h, conv_w)
+            output = conv * mask_reshape
             return output
 
         batch_size = features.size(0)