Abstract: The "unbalanced and inadequate development" is an important socio-economic problem facing China at this stage. This paper studies the evolution of the unbalanced pattern of population and economy by taking the districts and counties of the Chengdu-Chongqing Economic Zone as a sample, combined with the gravity center model, inconsistency index and imbalance index. We construct spatial autoregressive model (SAR) and spatial error model (SEM), and quantitatively analyze the influencing factors of regional gap from the perspective of new structural economics. It is found that: (1) the fluctuation range of population and economic gravity center is small, and the evolution of gravity center is mainly based on the "dual core" competition and cooperation situation of Chengdu and Chongqing, showing strong stability（2) The distribution of the inconsistency index between population and economy shows a circular pattern of "core-periphery". With Chengdu and Chongqing as the core areas, the inconsistency index is the lowest, showing a circle increasing trend（3) With the development of material capital, infrastructure and secondary and tertiary industries, the regional gap has been alleviated; Labor force and the secondary industry are the main factors affecting the regional gap and the main embodiment of spatial spillover effect. Based on the research conclusions, it is proposed to firmly establish the concept of integrated development, alleviate the economic constraints of administrative regions, and promote the flow of population and economy; give play to the leading role of the central city, formulate industrial policies according to local conditions, and build a coordinated development pattern of large, medium and small cities with dual cores as the center.
