Abstract: The flow field and infrared radiation in the 3-5 m model of an aero-engine exhaust system was built with lobed mixer, afterburner and cone. The calculated model was examined using the aero-engine ground infrared radiation characteristic test. The study of infrared radiation inhibitory schemes was established using low emissivity coating, components cooling, either alone or mixed. The results show that reducing the infrared emissivity of aero-engine wall restrains infrared radiation effectively in all directions except 90. With emissivity reduces by every 0.15, the infrared radiation of 0 could be reduced by about 16% when all components are coated whereas the inhibitory effect improves about 14% when partly coated. If the temperature of cone decreases by 300 K, the infrared radiation on 0-15 is reduced by 44%. If the temperature of divergent part of nozzle decreases by 25 K, the signature at 50 reduces by 8%. If combining the two methods, the signature is reduced by 80% on 0-5 and by 50% on 10-40.Along with the increasing angle of detection, the proportion of the solid radiation is found to be declining, and the inhibitory effect is decreasing.