diff --git a/README.md b/README.md
index d984c45..86d7a43 100644
--- a/README.md
+++ b/README.md
@@ -8,7 +8,7 @@ You can visit the latest [release](https://github.com/luosheng/OpenSim/releases)
 
 1. Install Homebrew: `/usr/bin/ruby -e "$(curl -fsSL https://raw.githubusercontent.com/Homebrew/install/master/install)"`
 2. Install Cask: `brew install cask`
-3. Install OpenSim: `brew cask install opensim`
+3. Install OpenSim: `brew install --cask opensim`
 
 ## TODO