Infrared images of an aircraft are needed for simulating the process of an infrared imaging guided missile attacking an aircraft. When the aircraft is attacked, it will maneuver to avoid the missile. Infared images detected by the seeker of the missile will change with the distance between the missile and the aircraft and the aircraft attitude. The changes need to be considered in the generated infrared image. In this paper, the formula for calculating the infrared radiation power received by the detector of the missile seeker was derived according to the law of conservation of energy and the law of blackbody radiation. The infulence of atmospheric transmittance, optic system transmittance and the responsivity of the dectector is also considered in the formula. The infrared radiation power of the faces of the three-dimensional aircraft model is calculated according to the formula. Then the power is converted into infrared gray value. We use OpenGL to trasform the three-dimensional aircraft model to infrared image according to the distance between the missile and the aircraft and the aircraft attitude. Finally, the infrared image can be genertated by convolving infrared image just generated and the point-spread function (PSF) of the optic system. A software is developed by us for simulating the infrared images of the aircraft.