We examine the impact of the enforcement of Urban and Rural Resident Pension Insurance (URRPI) on urban-rural income disparities with a staggered DID model based on the data from (Harmonized) CHARLS for 2011–2018 in China. We find that the URRPI integration materially narrowed income disparities between urban and rural households participating in different pension insurances. We also find heterogeneity in the reduction of income disparities on hukou, age, and health level. Possible mechanism include household incomes, working hours, non-agriculture employment and household intergenerational transfers. Our findings are of great significance for the improvement of the public pension insurance system.