In the research of space laser communication, due to the atmospheric attenuation, the structural design precision error, platform disturbance interference, etc., it brings a large problem for the system precisely alignment work. First, we study and analyse the influencing factors of speckle tracking, and then improve the tracking algorithm. A target matching algorithm for adaptive window sizes is designed for tracking target characteristics. Take the experimental platform with the crude complex shaft tracking platform to set up an experiment. The results show that comparison with the current common tracking algorithm, the design processing speed can reach 1 kfps, the target tracking position is substantially complicated with the real location, the target tracking accuracy is higher than 98%, and the tracking accuracy and algorithm robustness has a large improvement, with certain practicality.