Quick calculation of rocket exhaust plume radiation signal is of great significance for missile identification and tracking.Firstly,the flow field of liquid rocket exhaust is calculated by engineering empirical formula,and the radiation signal of liquid rocket exhaust plume is calculated by wide band k-distribution model.Secondly,compared with the line-by-line reference solution,it is found that the relative calculation error of wide band k-distribution model in the working spectrum region of the detector is basically less than 10 %.At last,the model is used to study the influence of flight parameters on the radiation signal of exhaust plume.The results show that the radiation intensity of liquid rocket exhaust plume increases with the increase of nozzle exit temperature,Mach number and non-calculating degree,and the variation trend of the radiation intensity of exhaust plume varies with the increase of altitude.