This paper constructs a dynamic panel model based on panel data from 872 counties （cities，districts） from 2014 to 2023，systematically examining the impact of rural finance on the urban-rural income gap from the perspectives of rural credit，agricultural insurance，and their synergistic effects. The findings reveal that higher levels of rural financial development contribute more effectively to narrowing the urban-rural income gap and achieving common prosperity. Specifically，rural finance primarily promotes income convergence through two mechanisms：compensating for insufficient fiscal expenditures and facilitating the flow of production factors and goods between urban and rural areas. Further heterogeneity analysis indicates that in regions with higher levels of rural financial development，greater economic growth potential，and major grain-producing areas，the synergistic effects of rural credit，agricultural insurance，and their combination exert stronger influences on narrowing the urban-rural income gap and fostering common prosperity，with variations in synergistic effects across different periods due to differing policy contexts.Based on the research findings，the paper proposes policy recommendations from three aspects：promoting the integrated development of rural finance，optimizing the rural financial ecosystem，and enhancing the precision of differentiated financial policies to narrow the urban-rural income gap and achieve common prosperity.