With the development of economy, China has officially entered the age of aging, which means that it will face serious population aging problems. With the weakening of the family pension model, it is urgent to develop a new pension model, and the research topic of mutual aid pension model emerges at the historic moment. The purpose of this article is to study the sustainable choice of mutual aid service models. Based on the background of population aging, this article introduces core concepts such as mutual assistance and elderly care services, time banking, and uses the theory of welfare pluralism, supply-side theory, and demand theory as the theoretical basis. An investigation and research on the status of "time bank" mutual aid elderly care service will be conducted, and the research results will provide ideas for the development of "time bank" mutual aid elderly care service. By investigating the views of senior citizens on Time Bank, this article has obtained 68%, 20%, and 12% of the three situations that are very satisfied, need improvement, and are very dissatisfied. It can be seen from this that the mutual assistance pension model has broad application prospects.