The invention discloses a chained STATCOM (static compensator) control system based on a serial communication manner, and the system comprises a master control case, a functional case, a phase control case and a unit controller, wherein the master control case and the functional case are used for performing control, monitoring and protection on the chained STATCOM; the phase control case is used for performing control, monitoring and protection on three phases of the chained STATCOM; the unit controller is used for performing control, monitoring and protection on a chain link unit of the chained STATCOM; and the serial communication manner is adopted among the master control case, the functional case and the phase control case.