diff --git a/modules/text/machine_translation/transformer/zh-en/requirements.txt b/modules/text/machine_translation/transformer/zh-en/requirements.txt
index 03e19dd532d1de97ffca5459e7b7ae0b37696665..e0442c89f12f991b8d9c3a7fa5aa1e98915abf34 100644
--- a/modules/text/machine_translation/transformer/zh-en/requirements.txt
+++ b/modules/text/machine_translation/transformer/zh-en/requirements.txt
@@ -1,3 +1,3 @@
-nltk==3.2.5
+nltk==3.4.5
 jieba
 subword-nmt