Based on small signal AC model of chain circuit static synchronous compensator(STATCOM),simplified STATCOM current control closed-loop system was proposed in this paper,the current regulator parameters of typical I and typical II model systems were optimized respectively,analysis shows that for current step response,the relative percentage of overshoot keeps unchanged in state of linear control,the absolute value of overshoot keeps unchanged in limiting nonlinear control state.The steady precision is a little poor but dynamic control precision is much better when applying proportional regulator to typical I model system,and it is suit for chain circuit STATCOM engineering installation.Simulation results in a-b-c coordinates show that with optimized control parameters of typical I model system the output current of chain circuit STATCOM can track reference changes fast,and the system has good stability and tracking precision.