Social adaptability is an important aspect of health. This study aimed to investigate the association between the community-based family doctor system (CFDS) and social adaptability and test the mediating effect. We used cross-sectional data from the 2018 China Health and Retirement Longitudinal Survey. A total of 13,895 samples were included. The OLS model, mediated effects model, and instrumental variables method were used for analysis. This study reveals a significant positive association between the CFDS and higher social adaptability among the middle-aged and older people in rural China. Outpatient utilization and life satisfaction were found to play a partial mediating role between the CFDS and social adaptability. Heterogeneity analyses revealed that the benefits of the CFDS varied across groups. It is necessary to improve the contracting rate of the CFDS among middle-aged and older populations in rural areas needs improvement. Additionally, family doctors should enhance their ability to detect health risks and diversify their services to cater to diverse needs.