A good first place to start. HKUST Library's "One stop" search (library + several other databases at once)
Statistical Databases - HKUST Library Subscribed or cataloged & + Open Data
Provincial statistics from are classed under HA4637 (e- versions available from 1989-)
Major City Statistics of China are classed under HA4638 (e- versions available from 1989-)
Or, you can also do a title search : 统计年鉴
ICPSR - Inter-university Consortium for Political and Social Research
After you sign-in to ICPSR, you can search and download data for later manipulation.
Asian Barometer - Public opinion data in Asia (uses Global Barometer survey as a model). Four waves of the AsiaBarometer have been conducted. Focus is on daily lives of ordinary people.
Asia Data Archive - from UC Irvine's Jack W. Peltason Center for the Study of Democracy (CSD) - includes many useful links
Go to Databses -> Humanities and Social Sciences to see other available databases.