The relay satellite, circulating on the GEO (Geographic Earth Orbit), can view the user spacecraft on the LEO (Low Earth Orbit) and the MEO (Middle Earth Orbit) directly as well, and view the ground station directly. The relay satellite can be seen as the bridge between the user spacecrafts and the ground station. The scheduling problem within TDRSS (Tracking and Data Relay Satellite System) is a very important problem. It analyses the characteristics and the constraints of the relay satellite scheduling, and then builds the CSP (Constraints Satisfaction Problem) model of the problem based on CSP theory. The CSP model is solved with STK (Satellite Tool Kits) and simulation method. Computational experiments indicate that the performance of the CSP model is quite good.