A high-precision satellite attitude simulation system for ground-based optical communication experiment was established.For the features of satellite trajectory, an improved auto-disturbance-rejection control algorithm was designed.The characteristics and principle of auto disturbance rejection control technology were introduced.Then, the improved servo algorithm was proposed and an selective integration item was added for ADRC algorithm.To achieve the dynamic error of ± 10″ for the system, a multi-threshold nonlinear function was designed, and a state determine module was added to change nonlinear function parameters in real time.At the same time, the setting principle of algorithm parameters was given, and the realized method and process for improved ADRC algorithm were presented based on the open servo functions of controller.The experimental results show that the system has a good capacity for acceleration and deceleration and the dynamics following error of tracking ramp signal is ± 6″.By contrast, the auto-disturbance-rejection control of anti-interference ability is superior to PID in the satellite attitude trajectory tracking, and the following error is ± 7″.These results meet the requirements of high-precision attitude simulation and also have stability and strong anti-interference ability.