In order to study the infrared radiation characters of C-17 transport aircraft, the body of aircraft was modeled and meshed based on the principle of infrared radiation, the structure and material of transport aircraft. The temperature distribution of skin was obtained through simulation of the flow field. Combined with the multiple occlusion algorithm of the surface, the total radiation intensity of aircraft in the infrared band( 8 μm~12 μm) was calculated with different Mach numbers in different directions of sight. The result shows that when the azimuth is 0° and the speed of aircraft is 1 Mach number, the radiation intensity can increase by 32% compared with the speed of aircraft is 0.5 Mach numbers. In this view, the Mach number has a great effect on the infrared radiation intensity whose increasing main source is pneumatic heating. When detecting from the front or the back, the infrared radiation intensity peak is approximately symmetrically distributed with the zenith angle. When detecting from the side, the infrared radiation intensity distribution is relatively average. In addition, the zenith angle has little effect on the intensity of infrared radiation.