The invention provides a robot control system and control method. The robot control system comprises a central control unit, a servo motor driver, an input-output module and an extended module. The central control unit is used for generating control parameters for a robot. The servo motor driver is connected with the central control unit through a POWERLINK bus, connected with a motor of the robot, and used for receiving the control parameters of the central control unit and controlling the motor through the control parameters so as to achieve movement control over the robot. The input-output module is connected with the central control unit through a POWERLINK bus and used for providing input and output functions. The extended module is connected with the central control unit through a TCP/IP communication protocol, and an independent processor is arranged in the extended module. According to the robot control system and control method, the problem of insufficient resources of the central control unit is solved effectively, and high efficiency of the central control unit is ensured.