In the context of the rural revitalization strategy， in order to achieve an effective connection between poverty alleviation achievements and rural revitalization， basic medical insurance needs to play a long-term role in poverty reduction and promote the sustainable development of ecological civilization and the economy in poverty-stricken areas. This paper uses rural household data from the China Family Panel Studies （CFPS） from 2012 to 2020， and employs multi-period Difference-in-Differences （DID） and Propensity Score Matching-Difference-in-Differences （PSM-DID） methods to examine the poverty prevention performance brought by the integration policy of urban and rural residents' medical insurance as a basic public service， and further studies the long-term effect of the policy on poverty reduction in rural families. The results show that the implementation of the integration policy of urban and rural residents' medical insurance can significantly reduce the vulnerability to poverty of rural families and also play a good long-term role in poverty reduction. Through heterogeneity analysis， it is found that the integration policy is more effective in reducing poverty among low- and middle-income groups， families with high vulnerability to poverty， families without elderly members， families without hospitalized members， and families in ecologically fragile areas. Mechanism tests show that the integration of urban and rural residents' medical insurance can play a long-term role in poverty reduction by increasing rural household capital accumulation， reducing healthcare expenditures， improving health status， and enhancing subjective social status.