Thanks stahta01 very much ! You give so valuable help.
I checked "Internationalzation" option and select "Chinese(Simplified)" and restart C::B, but the UI is still english. And I didn't get any error message. Then I read the wiki you told me and worked follow its directive (place zh_CN.mo, zh_CN.po, codeblocks.pot into {$CodeBlocks Install Dir}\share\CodeBlocks\locale\zh_CN folder and copy zh_CN.mo to codeblocks.mo). Then I start C::B and re-checked mark the "Internationalzation". After restart C::B, the UI is Chinese.
But now I meet another problem: I can't switch UI to English. I try to disable "Internationalzation", delete all the *.mo, *.po and *.pot files, but the UI is still Chinese. Who can give me any suggestions ? Thanks.