Abstract: A microcomputer controlled system for horizontal continuous casting machine driven by a servo-valve controlled hydraulic motor is introduced. Two withdrawing rolls with closed loop controlled speeds are adopted in the system. A difficult technical problem to be met with is that the system requires high accuracy in synchronization with the existence of a high in the tachogenerator. This is solved by adjusting the system parameters of two closed loop control circuits to make their performances as close as possible. The synchronization accuracy can reach 1%. The tested results of the system dynamic characteristics show that the frequency bandwidth of the system is 7 Hz. In addition, the system makes use of a BITBUS microcomputer having a high performance to realize the functions of giving command signal, display, print out, storage of technical parameters, treatment of defects and warning. The system has been put in use and running in a factory for one year.