diff --git a/README.md b/README.md
index 57af49881..0fca2a2c6 100644
--- a/README.md
+++ b/README.md
@@ -44,7 +44,8 @@ Your support will be really appreciated by me and other supporters!
 - [SeaweedFS Mailing List](https://groups.google.com/d/forum/seaweedfs)
 - [Wiki Documentation](https://github.com/chrislusf/seaweedfs/wiki)
 - [SeaweedFS White Paper](https://github.com/chrislusf/seaweedfs/wiki/SeaweedFS_Architecture.pdf)
-- [SeaweedFS Introduction Slides](https://www.slideshare.net/chrislusf/seaweedfs-introduction)
+- [SeaweedFS Introduction Slides 2021.5](https://docs.google.com/presentation/d/1DcxKWlINc-HNCjhYeERkpGXXm6nTCES8mi2W5G0Z4Ts/edit?usp=sharing)
+- [SeaweedFS Introduction Slides 2019.3](https://www.slideshare.net/chrislusf/seaweedfs-introduction)
 
 Table of Contents
 =================