Abstract: A numerical model was established for the photovoltaic phase change（PV-PCM）thermal management system,and the validity of model was verified by comparing with the experimental results. On this basis,the variation rule of different composite PCM physical property parameters（phase change temperature,mass fraction of expanded graphite,and thickness）on solar cell temperature within 24 h was studied. The effects of maximum temperature,duration of time above 45 ℃ and 41 ℃,and duration of night below 35 ℃were studied by orthogonal experiment method and visual analysis method. The influence of different types and numbers of heat dissipation fins on the working temperature of solar cell was further simulated to optimize heat dissipation structure of PV-PCM system.The research shows that the use of inward fin heat dissipation structure and the composite PCM with phase change temperature of40.2 ℃,mass fraction of expanded graphite of 15%,and thickness of 40 mm can minimize the maximum operating temperature of the solar cell,which is about 42 ℃.