The emergence of prefabricated buildings is helpful to solve the problems of serious energy consumption and environmental pollution in traditional cast-in-place buildings. However, the current unclear benefits of prefabricated buildings have led to great constraints on its development in China. Therefore, in order to clarify the comprehensive benefit level of prefabricated buildings and promote the development of prefabricated buildings, the comprehensive benefits of prefabricated buildings are analyzed from four aspects of economy, environment, society, and security, and 19 evaluation indexes of economic benefits, environmental benefits, social benefits, and safety benefits of prefabricated buildings are selected from the life cycle dimension in this paper. The comprehensive benefits of prefabricated buildings are constructed by using set pair analysis theory. Finally, through the analysis of the prefabricated building project in Hefei, the feasibility of the model was verified, and comprehensive benefit level of prefabricated buildings in Hefei was further judged. This paper provides a feasible and operable evaluation model for the comprehensive benefit evaluation of prefabricated buildings and also provides a theoretical support for the development of prefabricated buildings.