I’ve just tested beamer class with XeTeX. It works, but you got to specify the ‘dvipdfm’ option when calling ‘beamer.sty’. And seems beamer does not use chinese font for default. You got to set one yourself. Like this:

\DeclareFontFamily {U}{微软雅黑}{}
\DeclareFontShape{U}{微软雅黑}{m}{n}{<-> "Microsoft YaHei/n"}{}
\DeclareFontShape{U}{微软雅黑}{bx}{n}{<-> "Microsoft YaHei/B"}{}
\renewcommand{ \encodingdefault}{U}
\renewcommand{ \familydefault}{微软雅黑}

Thus you can use chinese font for the normal text. And also, you can use \renewcommand{\mathfamilydefault}{….} to set the default Math font family (If they are miss-displaied). Enclose shows the result~ SO PP :)