In order to make the infrared images of space target indicating its active state in orbit as real as possible, the contribution of the target spontaneous emission, the solar radiation, the earth radiation and the earth albedo radiation were considered. Combined with the information of the space target attitude and the detector parameters in orbit, a kind of infrared imaging simulation method was proposed in this article. Firstly, the method which is used to simulate the infrared imaging was explained in detail. Then, the method was used to simulate the infrared imaging of a simple cube satellite. The emulation results show that the method is feasible to simulate the infrared imaging of the space target, which has significant sense for the researches of target detection, recognition and tracking techniques.