Based on the infrared radiant theory，the infrared radiation characteristics of cruise missile cruise simplified engineering model is built for the different airspeeds and the lines of sight. The radiant missile-skin，hot spot，plume and the return radiant of sun and earth are calculated respectively. The results show that the main infrared radiant of cruise missile is the missile-skin，plume，hot spot，and the return radiant of sun and earth are neglected. Meanwhile，the main infrared radiant of cruise missile concentrates on the back. The infrared radiant of cruise missile changes fleetly by the different speed and the line of sight.