In recent years, in the construction of the general and branch libraries of public libraries, there has been a type of social branch construction model in which social forces provide venues and services, and libraries provide books and equipment. Different from traditional libraries, social branch libraries are for many users who are in fragmented time. This paper collects data through field research and network research, analyzes the embedded scene of the social branch library and the corresponding fragmentation time characteristics, summarizes service strategies and characteristics from three aspects of service environment, service content, and service methods, build a social branch library service model for users in fragmented time. The social branch should not be positioned as a simple reading place or a small public library. It is not advisable to copy the service model of traditional libraries and try to solve service problems completely with technology. The concept of “short, plain and people-oriented” should be adopted to lead the space design and reconstruct the service content and service mode.