Aiming at the laser communication of geosynchronous relay satellite to earth, a servo tracking system with multiple closed loops is designed, and a mathematical model of the tracking algorithm and a proportional-integral-differential control algorithm with actuator limit for miss distance compensation of faculae are analyzed. Additionally, the composition of the servo closed-loop control system in the satellite-ground link laser communication tracking system, the performance index and work pattern of each execution module are introduced. The operating principle of the servo closed-loop system and the optical closed-loop system is explained. According to the design of the miss distance extraction algorithm and the error compensation algorithm, the optical closed-loop tracking programs in image processing module and slave machine execution module are carried out. The weak beacon tracking experiments for the whole system are carried out under static and dynamic environments, and the tracking accuracy of ±20 μrad (3σ, σ is standard deviation) in dynamic environment and ±7.5 μrad (3σ) in static environment are obtained. The experimental results verify the feasibility and the preferable operability of the design of tracking loop, and indicate that the designed tracking system has high tracking precision.