According to the Ministry of Education in 2009 the leading law schools in China are:

1> Renmin University
2> China University of Political Science and Law
3> Peking University
3> Wuhan University
5> Jilin University
6> Tsinghua University
6> East China University of Political Science

http://news.xinhuanet.com/edu/2009-02/12/content_10807834.htm

See English version
http://translate.google.com/translate?hl=en&ie=UTF-8&sl=zh-CN&tl=en&u=http://news.xinhuanet.com/edu/2009-02/12/content_10807834.htm&prev=_t&twu=1

Of course there are many factors that you should take into account when choosing where to take an LLM. Also bear in mind that the Law School ranking doesn't necessarily correlate with the ranking of the LLM programs for foreign students.

For more information on China University of Political Science and Law you can visit the website here:
http://www.lawschoolchina.com