diff --git a/ChineseSegmentation/requirements.txt b/ChineseSegmentation/requirements.txt
index a3c8279..beae219 100644
--- a/ChineseSegmentation/requirements.txt
+++ b/ChineseSegmentation/requirements.txt
@@ -56,7 +56,7 @@ protobuf==3.4.0
 ptyprocess==0.5.2
 pyasn1==0.2.3
 pycparser==2.18
-Pygments==2.2.0
+Pygments==2.7.4
 pymongo==3.5.0
 PyNaCl==1.1.2
 pyparsing==2.2.0