In order to realize the miniaturization and integration design of space optical communication system, an integrated tracking system based on the array detector and the fast deflection mirror is established. By analyzing the principle of spot position detection of array detector, a centering algorithm is proposed. Firstly, the coarse centering strategy is designed by setting the threshold value. Then, the fine centering is completed by using the database query method. Thirdly, the infinite integral method is used to make the spot return to the origin. Finally, the correctness and feasibility of the algorithm are verified by building an experimental platform. The experimental results show that the tracking field of view can reach 70.3 mrad, which is about 3 times larger than that of the original algorithm, and the maximum tracking error is better than 1.8 μrad, which lays a foundation for further engineering application of the space optical communication system.