Based on the requirements for the sustainable development of prefabricated buildings, the construction stage with the most uncertain factors of prefabricated buildings is selected as the research object. From the six dimensions of social impact, environmental protection, resource utilization, economic objectives, construction technology and construction management, 24 detailed indexes are selected to establish a comprehensive evaluation index system for the sustainable level of prefabricated buildings. With the combination of interval analytic hierarchy process and grey clustering method, a comprehensive evaluation model of sustainable level of prefabricated building construction is constructed based on interval analytic hierarchy process-grey weighted clustering method. The evaluation model is used to comprehensively evaluate the construction sustainability level of a prefabricated building in Northwest China. the results show that the construction sustainability level of the assembly project is good sustainable, and the comprehensive evaluation results are basically consistent with the actual construction situation of the project. The feasibility and applicability of the evaluation model are verified.