According to the news released by the Embassy of China in the US, Chinese embassies will no longer issue passport extensions starting from January 1st 2007. A passport bearer can apply for a new one if the current one expires. 

China’s new Passport Act will take effect from next year. According to the new Passport Act, ordinary passports are valid for up to ten years. For people under sixteen years of age, ordinary passports are valid for up to five years only.