Abstract: In order to study the infrared radiation characteristics of BWB-UAV skin, infrared radiation intensity of typical stealth UAV of the 8-14 m band were calculated by the form of a combination of the flow field calculation commercial software and self-developed infrared computing software using the discrete transfer method. In the IR calculations, the emission and reflection of the solid wall of the engine, aircraft skin launch, gas, CO2, H2O and CO absorption and emission effects were talked into account. The results showed that: the Mach number is one of the impact factors that affecting infrared radiation characteristics on 8-14m band; The cooling, insulation measures that lowering the heat affected zone of the skin temperature fuselage engine or coating the infrared emissivity of materials on the fuselage skin can significantly reduce the infrared radiation characteristics of 8-14 m band. The conclusions provide a useful reference for the future aircraft infrared stealth design.