A temperature control system is designed based on the principle of thin film optics and heat transfer theory, it integrates the utilization of solar photovoltaicthermal effect by using a specific optical thin film to eliminate the ultraviolet radiation and a thermal circulation system to reduce its working temperature. After deducing the operational principle and design ideas of such system, the index are advanced, and the influence factors of ambient temperature and spectral transmittance to the heat transfer efficiency are analyzed. And then, several reasonable improved methods are put forward. A professional thinfilm design software named TFCalc is applied to design a particular optical thin film, simulation results show that the film can reflect a certain bandwidth of ultraviolet spectrum. The temperature control system has good practical value for the widely used photovoltaic power system.