<p>Social participation among migrants following resettlement is essential not only for their personal adaptation and development but also for maintaining social stability in resettlement areas. This research utilizes the Propensity Score Matching method to examine the impact of resettlement on rural residents’ social participation and to explore the underlying mechanisms, aiming to provide both theoretical insights and practical recommendations for optimizing future migration policies. The results reveal several key findings: First, resettlement significantly influences rural residents’ social participation, but the effects vary across three dimensions: social interaction engagement (SIE), civic engagement in public governance (CEPG), and participation in cultural and recreational activities (PCRA). Second, the residential environment exerts a suppressing effect on the pathway through which resettlement impacts rural residents’ SIE, while village cadre competency plays a mediating role in this pathway. Third, resettlement negatively impacts CEPG, while the residential environment exerts a reverse suppressing effect—an enhanced living environment could help reduce the participation gap in governance between relocated and original residents. Fourth, resettlement exerts a markedly positive impact on PCRA, and the residential environment serves as a positive mediator. Based on these empirical results, the research proposes the following strategic policy recommendations: strengthen the role of village committees by promoting social capital investment, organizing cultural and educational activities, and fostering a sense of community identity and collective consciousness among migrants; improve rural infrastructure and public service systems to rebuild social cohesion; and enhance the professional competence of grassroots cadres.</p>