The parameters of series compensator is designed by engineer trial-and-error method,so a design method of series compensator based on three-phase photovoltaic microsources is developed in this paper. Fistly,a mathematical model of current loop which is more suitable for designing the series compensator is developed for the PQ con-trol.On this basis,as for the constant value control system of current loop,it proposes three schemes about designing the parameters of the series compensator according to the control theories of linear control system.Finally,the scheme which has the best control performance in the example is developed by comparing .Then a simulation model of microgrid using master-slave control stategy is built in PSCAD/EMTDC,The simulation results show that the best sheme which obtain from therotical anlysis not only makes the PQ control peformance well but also has less effect on v/f control.