Abstract: In current times,the urbanization of China is confronted with serious challenge for sustainable development.This can mainly attribute to the negligence of the fundamental function of media-sized cities and small towns,namely the underdevelopment of these media-and small towns.The development of media-sized cities and small towns depend on the social and economic development of the rural areas.The inharmonious or disjointed relationship of cities and rural areas is the main barrier to the sustainable development of current urbanization of China. 

Key words: urbanization system, sustainable development, construction of small towns