Abstract: In order to study infrared radiation distribution along aeroengine and infrared characteristic of plume, the infrared radiation characteristic of an aeroengine was experimentally studied under the condition of ground engine testing. The experimental results show that the change of infrared characteristic along engine is small under different Mach number. The temperature of low compressor outlet increases with the Mach number. And the infrared radiation of engine's ektexine increases. The most intense infrared radiation is measured in the ektexine of blending box. Ektexine's radiation of blending box changes with non-linear feature and the increasing of the Mach number. The infrared radiation of plume is pyriform. The infrared radiation after engine is bigger than that before engine. Under the condition of ground engine testing, calculation program of infrared radiation for plume is presented. The computed results of directional radiance have tallied in general with the experimental results. Relative error between computed results and experimental results is not more than 15%. The spatial distribution of computed results is similar to experimental results.