Affected by the influence of the attitude variation and vibration of the satellite platform in the process of tracking and pointing, free space optical communication terminal will therefore reduce the tracking precision of the system. In order to improve the system′s ability for the purpose of resisting disturbance, on the basis of coarse tracking system, the cascade linear active disturbance rejection controller was put forward. The coarse tracking system used direct current brushless torque motor driving two-dimensional turntable as the actuator, and was controlled by the coarse tracking controller. Analysis of the system disturbance is required, for which the tracking differentiator is applied to extract. With azimuth axis of the two-dimensional turntable as the object, the cascade linear active disturbance rejection controller was applied to position loop and speed loop for the sack of active disturbance compensation through linear extended state observer. Therefore, double isolation of internal and external loop disturbance can be achieved, and the tracking precision shall be improved. The experimental analysis, and a comparison with the proportion integral derivation controller were also included. The research results show that there is a 50% decrease of standard deviation referred to the tracking error，when inputting 2 Hz, 5 Hz and 〖JP2〗8 Hz sinusoidal signals with the 〖JP2〗same disturbance signal simulation. 〖JP3〗At the same time, the observer′s〖JP〗 disturbance compensation effect in the circumstance of linear expansion was verified. A high tracking accuracy is still ensured when active disturbance rejection control is not sensitive to the frequency variation of inputted sinusoidal signal with changing frequency.