diff --git a/README.md b/README.md
index 8219f83..ae34736 100644
--- a/README.md
+++ b/README.md
@@ -4,11 +4,11 @@
 Download from release.
 
 ## Usage
-1. <kbd>Ctrl/?+O</kbd> to Open Image files.(\*.png/\*.jpg) (PS: The name of images files to be labeled should has the format of `image_{label}_timestamp.***`)
-2. <kbd>Ctrl/?+Alt+O</kbd> to Open saved label file.(\*.ljson)
-3. <kbd>Ctrl/?+S</kbd> to save label file.(\*.ljson)
+1. <kbd>Ctrl/⌘+O</kbd> to Open Image files.(\*.png/\*.jpg) (PS: The name of images files to be labeled should has the format of `image_{label}_timestamp.***`)
+2. <kbd>Ctrl/⌘+Alt+O</kbd> to Open saved label file.(\*.ljson)
+3. <kbd>Ctrl/⌘+S</kbd> to save label file.(\*.ljson)
 4. When the images have been loaded, use <kbd>&larr;</kbd> and <kbd>&rarr;</kbd> arrow keys to navigate from image to image.
-5. <kbd>Ctrl/?+&larr;</kbd>, <kbd>Ctrl/?+&rarr;</kbd> and <kbd>Shift+&larr;</kbd>, <kbd>Shift+&rarr;</kbd> arrow keys will help you to navigate faster to 10x and 100x respectively.
+5. <kbd>Ctrl/⌘+&larr;</kbd>, <kbd>Ctrl/⌘+&rarr;</kbd> and <kbd>Shift+&larr;</kbd>, <kbd>Shift+&rarr;</kbd> arrow keys will help you to navigate faster to 10x and 100x respectively.
 
 ## Development
 1. First: `npm install`
@@ -18,4 +18,4 @@ Download from release.
 ## Production
 1. First: `npm install`
 2. Webpack: `npm run postinstall`, and change `index.html` to use `bundle.js` built in last step.
-3. Start electron: `npm start`
\ No newline at end of file
+3. Start electron: `npm start`