Abstract: Two-city economic circle in Chengdu-Chongqing Region has become the fourth pole to promote China’s economic development, but the difference of urban development in the region is obvious, which leads to the problems of "central collapse". In this paper, principal component analysis-system clustering method and urban gravity correction model are used to discuss the clustering of urban development level and the intensity of inter-city connection in this region, and the development strategy is proposed. The results showed that: (1) Six main urban development level indicators were extracted by principal component analysis, and the cities in this region were divided into four categories through systematic clustering, including 2 Class I cities (Chongqing and Chengdu); 3 Class II cities (Yibin, Mianyang, Deyang); There are 6 Class IV cities (Neijiang, Suining, Leshan, Meishan, Luzhou, Zigong). (2) The development level of all kinds of cities is class Ⅰ＞Class Ⅱ＞Class Ⅳ＞Class Ⅲ. (3) The characteristics of the intensity of external relations of various cities are as follows: the intensity of Class I cities is the highest, but the gap between the two cities is the largest; The intensity of class II cities is second and the internal gap is the smallest. The intensity of Ⅲ and Ⅳ cities is weak but the internal difference is very small. The problems of urban development are as follows: type I cities mainly face problems such as prominent contradiction between people and land and great pressure on infrastructure; The second type of cities mainly face the problems of environmental pollution and small innovation. Category III cities mainly face the problems of backward industrial structure and weak regional characteristics. Class IV cities mainly face problems such as strong regional industrial convergence, serious brain drain and backward infrastructure.