diff --git a/mmdeploy/codebase/mmseg/deploy/segmentation.py b/mmdeploy/codebase/mmseg/deploy/segmentation.py
index 3b8adec1e..3dc471696 100644
--- a/mmdeploy/codebase/mmseg/deploy/segmentation.py
+++ b/mmdeploy/codebase/mmseg/deploy/segmentation.py
@@ -303,10 +303,10 @@ class Segmentation(BaseTask):
         params = self.model_cfg.model.decode_head
         if isinstance(params, list):
             params = params[-1]
-        postprocess = dict(params=params, type='ResizeMask')
         with_argmax = get_codebase_config(self.deploy_cfg).get(
             'with_argmax', True)
-        postprocess['with_argmax'] = with_argmax
+        params['with_argmax'] = with_argmax
+        postprocess = dict(params=params, type='ResizeMask')
         return postprocess
 
     def get_model_name(self, *args, **kwargs) -> str: