Abstract: It’s necessary to solve radiative transfer equation(RTE) of gaseous mediums when simulating the radiation of rocket engine exhaust plume.In the calculation model,spectral parameters of gaseous constituents were given based on single line group(SLG) band model;and RTE was settled by the use of discrete transfer method(DTM).Radiant heat flux emitted by exhaust plume was then achieved through integral wavelength.The program was then validated by applying to high temperature carbon dioxide gas with geometry of cylinder.Finally,radiant heat flux on different parts and instruments,which was emitted by main and attitude control engines,was calculated according to flow field of plume.The results of heat flux provide a reference for integrated design of the detector.