Here's something I found on trade.gov (International Trade Administration):
The following items are prohibited from entering China: arms, ammunition, and explosives of all kinds; counterfeit currencies and counterfeit negotiable securities; printed matter, magnetic media, films, or photographs that are deemed to be detrimental to the political, economic, cultural, and moral interests of China; lethal poisons; illicit drugs; disease-carrying animals and plants; foods, medicines, and other articles coming from disease-stricken areas; old/used garments; and local currency (RMB). Food items containing certain food colorings and additives deemed harmful to human health by the National Health and Family Planning Commission (NHFPC) are also barred.
Other Google search results seem to contradict this information, suggesting that I can bring up to 20,000 RMB. Which one is correct?