The variation ranges of species concentration, temperature and particle concentration of exhaust plume of the diesel engine with different load rate were tested in this article. Based on prototype experiment, the simulated generator and experimental platform of exhaust plume were built, and the effects of temperature, CO2, vapor and carbon soot on the infrared radiation characteristics of the exhaust plume were experimentally studied by infrared imaging. Experimental results showed that the temperature of the exhaust plume was the most important influencing factor for the infrared radiation characteristics, and the CO2 and carbon soot were also important influence factors too. However, the effects of the vapor could be neglected because of the slight influence on the infrared radiation characteristics of the exhaust plume.