Photovoltaic green roofs can contribute to energy conservation in buildings and the sustainable development of cities, but they have yet to be widely used due to many factors. Therefore, it is necessary to investigate the factors limiting the promotion of photovoltaic green roofs and to clarify their interactions. Based on the existing literature and expert recommendations, this paper summarizes 20 factors affecting its promotion. Fuzzy DEMATEL was used to analyze the causal relationship and importance of the influencing factors. A hierarchical structure was established using the interpretative structural model (ISM) to visually represent the layered structure and pathways of the factors. The role and status of each influencing factor were determined using the cross-influence matrix analysis method (MICMAC). Finally, the analytic network process (ANP) was combined with the overall influence matrix to determine the overall weight of each factor. Combined with the DEMATEL-ISM-ANP method, nine key influencing factors, namely, the lack of incentive policies, imperfect technical specifications and evaluation standard system, local economic development level, residents’ cognition, residents’ willingness, enterprises’ technical problems, the lack of relevant talents, the lack of capital investment, and cooperation mode, were finally identified and analyzed, and suggestions and strategies for improvement were proposed.