Three primary radiant points of the cruise missile, i.e. fuselage, hot spot and plume were analyzed, and an infrared radiation calculation model of cruise missile was established. Secondly, synthetically considering various factors such as height, slope and weather conditions, the influence of atmospheric attenuation was analyzed based on the theory of atmospheric transmission of the infrared radiation, and an theoretic model and calculation method of the atmospheric transmittance were established. Finally, take a certain cruise missile for example, the infrared radiation in 3~5�Eμm and 8~12�Eμm were computed based on the computing model. The atmospheric spectral transmittance and average transmittance and the infrared radiation attenuated were also calculated. An analysis of the results was also given.The results indicate that this is a simple method to calculate the infrared radiation of the cruice missile.