During the past 50 years,profound changes took place in the field of spatial structure of Chinese urban system.This paper will focus on the spatial relations(including network relations and territorial relations) in the inner urban system,and classify the ranks of spatial combination areas of Chinese urban system with different values of Distance Friction Coefficients b.Concerning Chinese urban system,two major regions(1st grade urban system) and seven sub-regions(2nd grade urban system) have formed,the Southern Major Region centralized with Shanghai and the northern one with Beijing.The Southern Major Region consists of four 2nd grade regional urban systems including the Shanghai System(Shanghai,Jiangsu,Zhejiang,Anhui and Fujian),Wuhan System(Hunan,Hubei and Jiangxi),Guangzhou System(Guangdong,Guangxi and Hainan) and Chongqing System(Chongqing,Sichuan,Yunnan,Guizhou and Tibet).The Northern Major Region consists of three 2nd grade regional urban systems including the Beijing System(Beijing,Tianjin,Hebei,Henan,Shandong,Shanxi,Shaanxi and Mongolia),Shenyang-Harbin System(Liaoning,Jilin and Heilongjiang) and Lanzhou-Urumqi System(Gansu,Ningxia,Qinghai and Xinjiang).Besides,64 local urban systems(3rd grade) have formed in the Chinese urban system,among which the 3rd Grade Shanghai System covers Wuxi,Ningbo,Hangzhou and Jinhua Systems,and the 3rd Grade Beijing System includes Beijing System and Datong System.