--- a
+++ b/tools/model_converters/twins2mmseg.py
@@ -0,0 +1,87 @@
+# Copyright (c) OpenMMLab. All rights reserved.
+import argparse
+import os.path as osp
+from collections import OrderedDict
+
+import mmcv
+import torch
+from mmcv.runner import CheckpointLoader
+
+
+def convert_twins(args, ckpt):
+
+    new_ckpt = OrderedDict()
+
+    for k, v in list(ckpt.items()):
+        new_v = v
+        if k.startswith('head'):
+            continue
+        elif k.startswith('patch_embeds'):
+            if 'proj.' in k:
+                new_k = k.replace('proj.', 'projection.')
+            else:
+                new_k = k
+        elif k.startswith('blocks'):
+            # Union
+            if 'attn.q.' in k:
+                new_k = k.replace('q.', 'attn.in_proj_')
+                new_v = torch.cat([v, ckpt[k.replace('attn.q.', 'attn.kv.')]],
+                                  dim=0)
+            elif 'mlp.fc1' in k:
+                new_k = k.replace('mlp.fc1', 'ffn.layers.0.0')
+            elif 'mlp.fc2' in k:
+                new_k = k.replace('mlp.fc2', 'ffn.layers.1')
+            # Only pcpvt
+            elif args.model == 'pcpvt':
+                if 'attn.proj.' in k:
+                    new_k = k.replace('proj.', 'attn.out_proj.')
+                else:
+                    new_k = k
+
+            # Only svt
+            else:
+                if 'attn.proj.' in k:
+                    k_lst = k.split('.')
+                    if int(k_lst[2]) % 2 == 1:
+                        new_k = k.replace('proj.', 'attn.out_proj.')
+                    else:
+                        new_k = k
+                else:
+                    new_k = k
+            new_k = new_k.replace('blocks.', 'layers.')
+        elif k.startswith('pos_block'):
+            new_k = k.replace('pos_block', 'position_encodings')
+            if 'proj.0.' in new_k:
+                new_k = new_k.replace('proj.0.', 'proj.')
+        else:
+            new_k = k
+        if 'attn.kv.' not in k:
+            new_ckpt[new_k] = new_v
+    return new_ckpt
+
+
+def main():
+    parser = argparse.ArgumentParser(
+        description='Convert keys in timm pretrained vit models to '
+        'MMSegmentation style.')
+    parser.add_argument('src', help='src model path or url')
+    # The dst path must be a full path of the new checkpoint.
+    parser.add_argument('dst', help='save path')
+    parser.add_argument('model', help='model: pcpvt or svt')
+    args = parser.parse_args()
+
+    checkpoint = CheckpointLoader.load_checkpoint(args.src, map_location='cpu')
+
+    if 'state_dict' in checkpoint:
+        # timm checkpoint
+        state_dict = checkpoint['state_dict']
+    else:
+        state_dict = checkpoint
+
+    weight = convert_twins(args, state_dict)
+    mmcv.mkdir_or_exist(osp.dirname(args.dst))
+    torch.save(weight, args.dst)
+
+
+if __name__ == '__main__':
+    main()