diff --git a/backend/Yiqi/Yiqi/requirements.txt b/backend/Yiqi/Yiqi/requirements.txt
index 2971ec8..84de368 100644
--- a/backend/Yiqi/Yiqi/requirements.txt
+++ b/backend/Yiqi/Yiqi/requirements.txt
@@ -65,7 +65,7 @@ jedi==0.11.1
 Jinja2==2.10
 lockfile==0.12.2
 luigi==2.7.1
-lxml==4.1.1
+lxml==4.6.3
 Markdown==2.6.11
 MarkupSafe==1.0
 matplotlib==2.1.2