The model of thermal infrared polarization properties of the metal surface was discussed. The statistic properties were considered in this model as well the surface shadowing effect.The relation between thermal infrared polariztion and irradiation angle is simulated for different surface roughness. The simulation results of smooth metal surface with roughness of 1.6 μm accord with the experimental data very well, but the simulation results of rough metal surface with roughness of 6.8 μm disaccord with the experimental data. After the shadowing effect of the rough metal surface is considered, the simulation results is improued greathy. The main related factors to determine the thermal polarization properties of the metal surface were discussed.