diff --git a/convlab/base_models/t5/nlu/nlu.py b/convlab/base_models/t5/nlu/nlu.py
index a5a6e6a23ec184b15fc073d88fa1a6b3fece34d8..4162aa3fd0ea6f4fbbde2620d45b9fb73e104875 100755
--- a/convlab/base_models/t5/nlu/nlu.py
+++ b/convlab/base_models/t5/nlu/nlu.py
@@ -1,10 +1,8 @@
 import logging
-import os
 import torch
 from transformers import AutoTokenizer, AutoModelForSeq2SeqLM, AutoConfig
 from convlab.nlu.nlu import NLU
 from convlab.base_models.t5.nlu.serialization import deserialize_dialogue_acts
-from convlab.util.custom_util import model_downloader
 
 
 class T5NLU(NLU):