On the basis of analyzing the research status of infrared imaging simulation systems, the typical small infrared target models and moving filtering algorithms are analyzed. According to the inner structure and materials of an air vehicle and the related theory of aerodynamics, physics and heat radiation, an infrared radiation model of the air vehicle is established in the aspects of scarfskin, pout and plume. By using the characteristics of the Digital Mirror Device (DMD) system, the model is simplified and the image generation rate is improved. Finally, the model and the algorithm are demonstrated on the DMD imaging simulation system platform. The result shows that this method has the features of clear image, high signal-to-noise ratio, high image generation rate, short storage time and stable tracking etc..