diff --git a/mmdet/configs/maskformer/maskformer_swin_l_p4_w12_64xb1_ms_300e_coco.py b/mmdet/configs/maskformer/maskformer_swin_l_p4_w12_64xb1_ms_300e_coco.py
index 2affe520918..deac8d7f876 100644
--- a/mmdet/configs/maskformer/maskformer_swin_l_p4_w12_64xb1_ms_300e_coco.py
+++ b/mmdet/configs/maskformer/maskformer_swin_l_p4_w12_64xb1_ms_300e_coco.py
@@ -10,7 +10,7 @@
 
 pretrained = 'https://github.com/SwinTransformer/storage/releases/download/v1.0.0/swin_large_patch4_window12_384_22k.pth'  # noqa
 depths = [2, 2, 18, 2]
-model.update(
+model.merge(
     dict(
         backbone=dict(
             _delete_=True,