Under the background of prominent rural pension problems and national advocacy of mutual assistance for the aged, in order to explore whether mutual assistance for the aged is universal across the country. Based on the special survey data of rural mutual support for the aged in Shandong Province in 2020, logit, Probit and PSM models were used to test the influence of children’s going out on the willingness of the elderly to participate in the mutual support in rural areas, and the mutual support services needed by the elderly were analyzed. Theoretically speaking, when families are generally unable to solve the problem of old-age care, the abundant service supply of mutual assistance and the concept of intergenerational relay of mutual assistance force, combined with the tradition of spontaneous mutual assistance in small-scale peasant society, will help the old-age care responsibility transfer from family and clan network to neighborly network in the rural society with the pattern of difference. The results show that the willingness of parents to participate in mutual support is significantly increased by their children’ s going out. Moreover, the smaller the number of children and siblings, the higher the importance of pension as a source of livelihood, the stronger the promotion effect. The lower satisfaction of family support, the heavier burden of family support, and the worry about the future are the potential reasons for the elderly to participate in mutual support when their children go out. The elderly’s demand for mutual support services is divided into health support, life care, farm work help and spiritual comfort according to the expectation intensity. The above results indicate that on the background of rural urban population flow, small family size and pension system is constantly improving mutual support is suitable to solve the rural ageing problem in china. The article suggests that by strengthening health support services, expanding life care services, launching farm work services, deepening spiritual consolation services, consolidating financial security, improving economic independence and other ways, to enhance the service capacity of mutual support, promote mutual support take root and sustainable development in rural areas.
