for site which language is chinese what should i choose @font-face or sIFR for custom fonts? and which charset i should choose?
Any typography, license free fonts suggestion would be appreciated.
Personally I'd avoid font embedding for Chinese. The fonts are just so big, it's a lot to download. And there are more potential issues with different anti-aliasing modes: many CJK fonts are likely to render horribly with anti-aliasing off, and the default horizontal-only anti-aliasing of ClearType applies poorly to ideographs that weren't specifically designed for it, as they tend to have many near-horizontal lines (which Latin typically doesn't).
So I'd go with the image replacement for now.
The charset for any modern web application should be UTF-8. There may still occasionally be a need to encode to a legacy DBCS such as GB (maybe for sending mail to old mobile phones or some broken webmail services), but database content and normal web page serving should all be UTF-8.