A mathematic model of a trough concentrating solar PV/T system has been established and verified with experimental data. The calculation based on the model is agreeable with experimental results, the errors between calculations and experiments are less than 5%, which indicates that the model is valid. Through the model, the performance of the trough concentrating solar PV/T system based on super cells is analyzed systematically with internal and external parameters of PV/T system. The internal parameters include optical efficiency of mirror, width of focusing line, thermal conductivity of heat sinking tape and thermal absorption of the lighting plate, while the external parameters include the wind speed and the solar direct radiation. A large number of simulations were undertaken to test the thermal, electricity, total and exergy efficiency of PV/T system for variation of the design parameters. The result indicates that the optical efficiency of mirror has more effect on the performance of system than others, the total and exergy efficiency increase 0.9 times and 0.5 times respectively with the optical efficiency of mirror increasing from 0.5 to 0.95. Other parameters also have strong effects on the performance of system. All these works benefit to further study in optimization design of the system.