An infrared image simulation method is proposed. First, the radiation intensity and spectral distribution of a target in the detection waveband are analyzed and simulated. Then, the corresponding atmospheric effect model and imaging system effect model are established according to the modulation transfer functions of the atmosphere and the imaging system. Finally, in accordance with the infrared imaging principle and the detection parameters, the simulation model of the target is fused with the infrared image of the real background by using the image synthesis algorithm. Thus, the images of the target and scene are fast generated. The reliability of the scene is improved by combining the theoretical data with the experimental data. The method is of reference value to the testing and evaluation of an infrared search and track system.