The research on infrared radiance characterization of the satellite is of great significance in satellite infrared detection and recognition and the satellite infrared stealth design. In this paper, firstly, the radiant heat flux of satellite was calculated. Secondly, each surface temperature changed with orbit cycle was calculated. On this basis, the self-emitted infrared radiation and its reflecting infrared radiation from the environment of the various satellite surfaces were calculated, thus a mathematical model to calculate the satellite infrared radiant periodic characteristics was established. Finally, taking a hexahedron satellite in an orbit for instance, the radiant luminance of MIR and FIR in atmospheric window and its change with time on its body's six different surfaces during the period on the orbit were calculated. Results can provide the reference for satellite infrared detection and infrared stealth design.