Trajectory tracking rotating mirror has become a mature and reliable method to acquire the image of a flight projectile. Servo motion controller is the core component of the tracking rotating mirror, and the overall system performance is determined by the accuracy and real-time. The paper proposed a design scheme of a servo control system of tracking rotating mirror based on the ARM system principles. We give the detailed introduction of the controller principles, hardware and software design. The results show that the system achieves the control accuracy of 0.4° and the control response time of 1ms minimum.