diff --git a/requirements/docs.txt b/requirements/docs.txt
index b698928f9..d263b4808 100644
--- a/requirements/docs.txt
+++ b/requirements/docs.txt
@@ -1,4 +1,5 @@
 docutils==0.16.0
+markdown<3.4.0
 myst_parser
 -e git+https://github.com/open-mmlab/pytorch_sphinx_theme.git#egg=pytorch_sphinx_theme
 recommonmark