This paper is aiming to study the approach of generating infrared picture about the earth background.The whole earth surface is divided into a number of surface elements according to the surface features.Taking into account the effects of several factors such as the atmospheric transmission, surface type, surface longitude and latitude as well as the surface altitude, the temperature models and the infrared radiation models for each surface element are developed. The models are numerically computed to obtain the temperature distributions and the infrared radiance of the earth surface. According to the known visual angle and position of a possible infrared detector in the outer space, the 3!D image of the infrared radiance of the earth background is dynamically visualized. The simulated images are vivid. The generated infrared image can be used for the identification of the infrared target and the simulated application