Abstract: In rural areas, mutual support for the elderly is one of the effective models to solve the shortage of elderly care service. With the goal of improving the benefit level of mutual support for the elderly, based on the Anderson model of health service accessibility, theory of planned behavior and self-determination theory, the article constructs a theoretical analysis framework from three dimensions of potential accessibility, realized accessibility, and sustainable accessibility, and constructs an empirical model. The research finds that propaganda intensity has an obvious positive effect on potential accessibility, and the effect includes individual participation, role shaping, altruistic motivation and willingness to help each other. Facility provision accelerates the process of potential accessibility to realized accessibility and the process includes precise positioning, supply based on demand, spontaneous participation and group effect. Incentive standard and social participation have a positive impact on the process from realized accessibility to sustainable accessibility and the process includes interest incentives, clear responsibilities, perfect system and scale effect. According to the results, some suggestions are offered, like stimulating the willingness to participate, locating the needs, improving the participation mechanism of mutual support and so on, to improve the accessibility of mutual support for the elderly.