The 3D geometric model of airplane tail nozzle is established,and the numerical simulation of the flow field outside the nozzle is carried out by Fluent 6.3.26 software.The flow field data of tail flame such as temperature and pressure are obtained based on the assumption of engine complete combustion.The K-distribution method was used to calculate the radiation parameters of the tail flame.The infrared radiation characteristics of the gas were calculated by Reverse Monte Carlo method (RMC),and the infrared radiation image of the tail flame was obtained.