diff --git a/mmdet/models/dense_heads/rtmdet_ins_head.py b/mmdet/models/dense_heads/rtmdet_ins_head.py
index 261a57fe485..8d2cddd576c 100644
--- a/mmdet/models/dense_heads/rtmdet_ins_head.py
+++ b/mmdet/models/dense_heads/rtmdet_ins_head.py
@@ -500,8 +500,8 @@ def _bbox_mask_post_process(
                 mask_logits = F.interpolate(
                     mask_logits,
                     size=[
-                        math.ceil(mask_logits.shape[-2] * scale_factor[0]),
-                        math.ceil(mask_logits.shape[-1] * scale_factor[1])
+                        math.ceil(mask_logits.shape[-2] * scale_factor[1]),
+                        math.ceil(mask_logits.shape[-1] * scale_factor[0])
                     ],
                     mode='bilinear',
                     align_corners=False)[..., :ori_h, :ori_w]