Abstract: Predigesting geometrical model of a certain aircraft was established, and its flight path was set. Aerodynamic heating and radiation from sun, ground and atmosphere were considered comprehensively, then physical models of heat conduction were founded against three shielding coatings with different emissivity and physical characteristic of stealth aircraft skin. Based on one dimensional heat conduction equation, temperature distributions of skins with different emissivity were calculated between 12:00 pm and 12:45 pm. Finally, influence of environment radiation was considered, the infrared radiant intensity distributions of skins with different emissivity were calculated numerically in 3-5 m and 8-14 m. The result improves that with skin emissivity reducing the infrared radiant intensity of skin diminishes at a certain extent, but due to influence of environment radiation, the effect of aircraft infrared stealth is not ideal only by skin emissivity decreasing.