Social insurance is the core content of China’s social security system,it plays an important role in promoting social stability, equity, progress and promoting regional high-quality development.By using the methods of entropy, spatial autocorrelation and geographic detector, this paper analyzes the spatial-temporal evolution and influencing factors of social insurance level in the Yangtze River Economic Belt from 2012 to 2018. The results are as follows: (1) The overall social insurance level in the Yangtze River Economic Belt is growing rapidly, the relative differences between provinces are gradually decreasing, and the social insurance level is east > west > central; (2) Most of the provinces in the Yangtze River Economic Belt have relatively low social insurance levels during the study period, with significant clustering characteristics overall, and hotspot and coldspot areas show more stable spatial evolution characteristics; (3) The spatial divergence characteristics of the social insurance level in the Yangtze River Economic Belt are influenced by various factors, with urban residents’ per capita disposable income, total wages of urban unit employees and per capita GDP being the leading factors.In the future, the Yangtze River Economic Belt should develop the social insurance system as a whole and gradually narrow the gap between the eastern, central and western social insurance levels.