Acquisition, tracking and pointing(ATP)system is the core of high speed and large capacity of laser communication in atmosphere, spot jitter generated by the disturbances among long distance laser communication has seriously affected the precise alignment between laser communication terminals, and greatly reduces the stability of the communication link and quality. In order to suppress the facula dithering, improve the accuracy of target tracking, this paper proposes an improved fast steering mirror control method. Analyzes the features of self-adaptive control and conventional PID control, and discusses the advantage of composite control with the two algorithms, proposes model reference self-adaptive control algorithm of PID, according to the Lyapunov theory, and makes algorithm simulation analysis with the conventional PID and model reference self-adaptive and PID compound control and do closed-loop tracking experiment of actual facula dithering. The experimental results show that, the adaptive PID controller obtains the overshoot is 2%,rising time is 3ms,trackingaccuracy better than 2 microradian, overall better than the conventional PID control algorithm. Compared with the traditional PID control, control algorithm which is proposed in this paper has better inhibition of spot jitter.