diff --git a/requirements.txt b/requirements.txt
index 0f3479e..fc4a939 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -38,7 +38,7 @@ jsonschema==2.6.0
 landslide==1.1.3
 leancloud==2.1.5
 Logbook==1.1.0
-lxml==3.3.3
+lxml==4.6.3
 Markdown==2.6.11
 markdown2==2.3.4
 MarkupSafe==1.0