Background radiation characteristic is an important part of the target infrared radiation.For the typical stealth UAV,the effect of the background radiation on target infrared radiation was theoretically analyzed,and the mathematical model of the target infrared radiation was established.Using the numerical simulation method,the target infrared radiation characteristic under the background radiation was calculated,and the effect of background radiation on the target infrared radiation characteristics was analyzed.The results provide a reference for the aircraft infrared detection and infrared stealth design.