
All of Stata's interface—all menus and all dialogs—is available in Chinese.
If your computer language is set to Chinese (zh_CN) and its region is set to China, Stata will automatically default to its Simplified Chinese setting. To change languages manually using Windows or Unix, select Edit > Preferences > User-interface language... using Mac, select Stata > Preferences > User-interface language... You can also change the language using the set locale_ui command.
Learn more about the set locale_ui command at [P] set locale_ui.