Abstract:  Based on the new development concept, an evaluation index system of the coordinated development level of the high-quality development of the Yangtze River Economic Belt was established in this study. Focusing on the four core elements of coordinated development: urban and rural areas, regions, elements and nature, 20 specific indicators were selected for 108 cities and prefectures in the Yangtze River Economic Belt from 2010 to 2020, aiming to analyze the spatial heterogeneity and spatio-temporal evolution of the coordinated development level of the Yangtze River Economic Belt. The results show that: Firstly, the downstream areas of the Yangtze River Delta have higher development levels than other regions in all evaluation dimensions and have significant spillover benefits, indicating a great radiation effect on the whole Yangtze River Economic Belt. Secondly, the analysis of internal gravitational force of urban agglomerations indicates that the cohesion of the downstream area urban agglomerations occupies an absolute advantage, and the three national urban agglomerations all show a strong growth trend of strengthening. Thirdly the provincial development level is obviously affected by the provincial capitals. The provinces with high-developed capital show a clear skew in resources, while the similar urban agglomeration with provincial capital as the core show an imbalance in overall development. Therefore, based on the spatio-temporal evolution regulation and current characteristics of the coordinated development of the Yangtze River Economic Belt from the perspective of high-quality development, our study proposes policy suggestions on the implementation of differentiated development strategies and coordinated regional development, with a view to promoting the coordinated development level of the Yangtze River Economic Belt.