Open System Preferences - click "international" - select "input" tab - check
"简体中文" and "繁体中文" boxes, then close System Preferences. After this, you will find small flag icon on top menu bar of Finder and all other applications, click on it you can choose different language input. After choosng Chinese, there will be a small pencil icon appear on right side of language icon, which allow you to choose different input methods: 简体有拼音，五笔，区位等七种，繁体有拼音，注音，大五码等八种。
