diff --git a/opensora/models/vae/vae_3d.py b/opensora/models/vae/vae_3d.py
index 089b8a0..9f0badb 100644
--- a/opensora/models/vae/vae_3d.py
+++ b/opensora/models/vae/vae_3d.py
@@ -1,7 +1,6 @@
 import functools
 from typing import Any, Dict, Tuple, Type, Union, Sequence, Optional
 from absl import logging
-import ml_collections
 import torch
 import torch.nn as nn 
 import numpy as np