diff --git a/README.md b/README.md
index ce53186ee2eecec44c21635ae20b487de8e5d4c2..27c2474ebb4b5941189ff7d27b87e081bacefa4e 100644
--- a/README.md
+++ b/README.md
@@ -4,7 +4,7 @@ CEPC offline software prototype based on [Key4hep](https://github.com/key4hep).
 
 ## Quick start
 
-Start the container in lxslc7:
+Start the container in lxslc7 (OS: CentOS7):
 ```
 $ /cvmfs/container.ihep.ac.cn/bin/hep_container shell SL6
 ```