A novel multifunctional integrated solar energy utilization system is proposed in view of the lack of research on solar energy technology applied in light steel prefabricated buildings. To better analyze the performance of the system， theoretical models for generation efficiency， generation power， thermal efficiency and hot water temperature are established based on system characteristics and energy conversion relationships. The influences of design parameters including solar irradiance， capacity of hot water tank， preset temperature of hot water tank and system series quantity on electrical and thermal performance of the system are analyzed by using these established models. The results show that， to obtain higher thermal and electrical efficiency， it is essential to comprehensively consider the local solar irradiance and the required hot water temperature to determine the capacity of the hot water tank， the preset value of water temperature and the number of series and parallel connection of the system. Under given collector parameters， when the solar irradiance reaches 550 W/m2， the design requirements can be met. At this time， the hot water temperature of the high-temperature array of the system is 74.5 ℃， the thermal efficiency is 52.6%， the hot water temperature of the low-temperature array is 52.3 ℃， the thermal efficiency is 60.4%， the power generation is 58 W， the power generation efficiency is 9.46% and the comprehensive utilization efficiency of solar energy of the system is 79.1%. Compared with the experimental results of literature research， the overall solar energy utilization efficiency is increased by 30%. The proposed system provides a new idea for the design of solar energy utilization systems and integrated design with light steel prefabricated buildings in the future， which has important reference significance for the efficient utilization of solar energy.