Taking 71 cities in the three major urban agglomerations of the Yangtze River Economic Belt as the research object, the coupling coordination degree model is used for a measurement of the coordinated efforts of pollution reduction and carbon reduction in the three urban agglomerations from 2011 to 2020, followed by an inquiry into the spatiotemporal heterogeneity of the influencing factors in each urban agglomeration by using GTWR model. The results indicate that during the research period, the overall coordination of pollution reduction and carbon reduction among the three major urban agglomerations in the Yangtze River Economic Belt shows an upward trend. By 2020, all three urban agglomerations have reached a coordinated state of pollution reduction and carbon reduction, with the degree of coordination in a descending order being the Chengdu-Chongqing urban agglomeration, the middle reaches of the Yangtze River urban agglomeration, and the Yangtze River Delta urban agglomeration. The regression results of the influencing factors show that urbanization, scientific and technological innovation and environmental regulation can promote the synergy of pollution and carbon reduction, while population agglomeration and industrial structure can inhibit the reduction of pollution and carbon reduction. However, the level of economic development and opening up to the outside world exhibits a significant spatio-temporal heterogeneity among the three major urban agglomerations. Based on this, differentiated collaborative governance strategies have thus been proposed for pollution and carbon reduction from the perspectives of economic development, social progress, technological innovation, and policy regulation, so as to help achieve the pollution and carbon reduction goals of various urban agglomerations, even including the Yangtze River Economic Belt.