diff --git a/ktransformers/operators/experts.py b/ktransformers/operators/experts.py
index 10e3a66..88960c7 100644
--- a/ktransformers/operators/experts.py
+++ b/ktransformers/operators/experts.py
@@ -459,9 +459,9 @@ class KExpertsTorch(KExpertsBase):
                     self.up[i] = w["up"][i, ...].to(device=device, dtype=self.dtype)
                     self.down[i] = w["down"][i, ...].to(device=device, dtype=self.dtype)
         
-        self.up = torch.cat(self.up, dim=0)
-        self.gate = torch.cat(self.gate, dim=0)
-        self.down = torch.cat(self.down, dim=0)
+        self.up = torch.stack(self.up, dim=0)
+        self.gate = torch.stack(self.gate, dim=0)
+        self.down = torch.stack(self.down, dim=0)
         return 
 
     def unload(self):