Abstract: The paper introduced working principle and control method of STATCOM and proposed a design scheme of a STATCOM controller. It also gave some problems and corresponding solutions including communication between the master controller and the slave one, jitter elimination in process of data transceiving of displaying CPLD, short circuit in bridges of IGBT and procedures fleet. The controller is based on the theory of hysteresis instantaneous comparison control and uses a mode of master-slave controller. The master controller and the slave one both adopt DSP+CPLD structure so as to improve operation speed and real-time performance of the STATCOM controller.