A geometric model of Coude type laser communication terminal is established. Its polarization state transfer characteristics are analyzed by using three-dimensional polarization state tracking algorithm. The system polarization state transfer matrix is obtained, and the relationship between azimuth, elevation angle and polarization extinction ratio, phase delay angle of Coude type laser communication terminal is established. Numerical simulation is carried out on polarization state of the output signal light. Results show that the output signal polarization state of Coude type laser communication terminal is closely related to the terminal azimuth and elevation angle, which provides a reference for real-time control of polarization state in coherent space laser communication system.