Following the description of the inequality of China's urban per capita GDP,this paper explores the reason of the inequality through the multiple regression analysis.The results show that the economic development has been quite uneven among Chinese cities nowadays.The capital investment has most significant influence upon per capital GDP,the industrial structure follows.The Foreign Direct Investment only can influence the eastern cites group and the large and medium sized cities group.The city population size does not have much relationship with per capita GDP,even has a negative impact on the group of large cities.These findings indicate that the transition from extensive to intensive economic growth is very imperative and that the economic development of cities cannot benefit by blindly increasing their population size.