Abstract: To solve the maintenance problem caused by the different service lives between the heat collection part and power generation part of the photovoltaic/thermal (PV/T) module, outdoor test equipment and simulation model are proposed. The performance and applicability for different cities of the PV/T module with/without insulation layer are studied. The results show that the average thermal efficiency and solar energy utilization of PV/T system with insulation layers are 43.20% and 60.16%, respectively. The intercept and slope of the instantaneous thermal efficiency curve of the PV/T system with insulation layers are 48.65% and 11.68 W/m²·K, respectively. The average thermal efficiency and solar energy utilization of the PV/T system without insulation layer are 34.16% and 51.99%, respectively. The intercept and slope of the instantaneous thermal efficiency curve of the PV/T system without insulation layer are 50.49% and 19.73 W/m²·K, respectively. The thermal efficiency and solar energy utilization vary little with the increase of water mass flow rate caused by the temperature stratification of the tank within the range 0.013~0.060 kg/s. The annual average operating temperature of PV/T modules with insulation layer is 0.21~1.12℃ higher than that of PV/T modules without insulation layer, and the annual average power generation efficiency is relatively lower by 0.44%~0.82%. The PV/T system without insulation layer can meet the standards of Sanya, Kunming, Xi'an, Guangzhou, Hangzhou, and Wuhan for 45℃ hot water.