Abstract:At present, large-scale population flow has become a major trend in China. Using the huge potential contained in the floating population to promote the development of regional innovation capacity is an important means to achieve high-quality economic development in the Yangtze River Economic Belt. It is worth exploring whether there is an intrinsic relationship between population flow and regional innovation capacity. The Yangtze River Economic Belt includes the Yangtze River Delta city cluster, the city cluster in the middle reaches of the Yangtze River, and the Chengdu-Chongqing city cluster, with a geographic scope spanning the three major segments of east, center, and west of China. Studying the impact of population flow on regional innovation ability provides an important reference for enhancing the overall innovation strength of China. On the basis of theoretical analysis, this paper uses the panel data of 70 cities in the three major urban agglomerations of the Yangtze River Economic Belt from 2006 to 2020, and uses the general panel model and the Spatial Durbin Model to analyze the correlation between population mobility and regional innovation capacity. The results show that population flow (population inflow) has a significant promotion effect on regional innovation capacity. After considering the spatial dependence, population flow not only directly improves regional innovation capacity, but also has a strong spatial spillover effect. The spatial mobility of labor force population has a significant impact on regional innovation capability, while the influx of the elderly population cannot play a role at the beginning, but when it reaches a certain scale, the influx of the elderly population can promote the development of regional innovation capability. The effect of population flow on regional innovation capacity has significant spatial differentiation characteristics. Population flow has an obvious innovation promotion effect on the Yangtze River Delta Urban Agglomerations, super megacities, and cities close to provincial capital cities, while it has a relatively small impact on the innovation capacity of the city agglomerations in the middle reaches of the Yangtze River, the Chengdu-Chongqing urban agglomeration and large cities. Based on the review of existing literature, the possible marginal contributions of this paper are as follows: firstly, in terms of theoretical analysis, this paper not only explains the relationship between population flow and innovation ability, but also analyzes the impact of population flow of different ages on innovation ability; secondly, in terms of empirical analysis, this paper not only studies the correlation between population flow and regional innovation ability, but also fully considers the spatial correlation. On the basis of constructing a common spatial weight matrix, the gravity matrix of economic connection is added to analyze the spatial spillover effect of population flow on regional innovation ability through the spatial econometric model; thirdly, in terms of research depth, this paper further analyzes the heterogeneity of population flow direction, population age structure, city groups, urban population size, and urban geographical location to explore the differential impact of population flow on regional innovation ability. According to the research conclusions of this paper, in order to rationally guide the population flow and promote regional innovation, this paper puts forward the following policy recommendations: firstly, to tap the potential of the population of all ages and make full use of the advantages of the labor force and the elderly population; secondly, to take action in accordance with the local conditions of each city; thirdly, for cities with different population sizes, to formulate differentiated policies to guide the population flow.