With regard to meeting the highly dynamic and steady-state performance of the coarse tracking system used for laser communication in a satellite， under the action of the step signal， the ordinary PID control has drawbacks such as large step response overshoot and long adjustment time to fulfill the engineering requirements. This study uses permanent magnet synchronous motor （PMSM） as the control object to establish a three-loop control model of the coarse tracking system and performs MATLAB simulation analysis. An adaptive gain control is proposed on the basis of ordinary PI control， and theoretical proof and simulation are executed. It provides a new method for the tracking system to shorten the adjustment time and reduce the overshoot. The tracking system is controlled by the FPGA main control unit. In the ground test， under the excitation of a 187.25 μrad （500 yard） step signal， the improved adaptive gain control strategy is better than ordinary PI control， the overshoot is reduced from 35.8 % to 10%， and the adjustment time of the system is shortened from 100 ms to 70 ms. The state accuracy is maintained at 2.247 μrad（±3 yards）， and the control performance is significantly improved. Under orbital conditions， the adaptive gain control strategy shows good control performance， meeting the high precision requirements of the tracking turntable used for inter-satellite laser communication， and it has reference significance for the design of other high-precision servo systems.