The infrared characteristics of an air target’s scarfskin are very important for the detection and identification of the air target. Referring to a certain oversea air target, its flight path was set. Aerodynamic heating and radiation from environment being considered comprehensively, one dimensional heat conduction equations were established about the air target’s scarfskins. These equations were solved with backward difference approximation, and then temperature distributions of the scarfskins were achieved in 4:00 AM~4:45 AM and 12:00 PM~12:45 PM. Finally, influence of environment radiation being considered, while time and space changing, the infrared radiant intensity distributions of the scarfskins were calculated numerically in 3～5 μm and 8～14 μm. The result shows that far infrared radiant intensity of the scarfskins is far more than their middle infrared radiant intensity and the infrared characteristics have few changes when the air target flights.