A time bank is usually regarded as a new form of volunteer service. Focusing on the dimension of non-compensation, we define time banks’ special volunteer service as low-paid volunteer service, to distinguish it from the traditional unpaid volunteer service. In recent years, these two kinds of volunteer services have simultaneously emerged in China's time banks, which we called "hybrid volunteering". And it has a positive impact on the sustainable development of time banks. Based on the multiple institutional logic perspective and case analysis, we find the hybrid volunteering is mainly generated from three mechanisms: Through the division and distribution of voluntary labor reciprocation by time currency, the integration process design of low-paid volunteer service and unpaid volunteer service is realized; The public welfare fund manages the donation of time currency separately, to avoid circulating with time currency from low-paid volunteer service; An exclusive time bank platform is also set up to mobilize party members to participate in unpaid volunteer through grassroots party building, cooperating with a separate public welfare fund to organize party member volunteers independently. In such complex institutional environment, the competition between market logic and public welfare logic may lead to the failure of hybrid volunteering, while the intervention of government logic and performance of the value guidance and resource integration functions of party building can alleviate it.