Studying the infrared radiation characteristics of the side jet of an aircraft model in a wind tunnel environment and its measurement correction methods is of great significance for conducting wind tunnel tests. When measuring the infrared radiation of the side jet of an aircraft in a wind tunnel environment, the radiation generated by the inner wall of the wind tunnel and the wall of the aircraft model is an interference source for the infrared measurement of the jet. By solving the mass equation, momentum equation, energy equation and component transfer equation, the flow field of the side jet of the aircraft model in a wind tunnel environment and the infrared radiation characteristics of each radiation source in the 3－5 m band are numerically simulated. The research results show that with the increase of the Mach number Main at the inlet of the test section, the radiation intensity of the inner wall of the wind tunnel and the wall of the aircraft model increases, and the integrated radiation intensity of the side jet first decreases and then increases. By analyzing the radiation characteristics of each radiation source, the variation law of the integrated radiation intensity of each radiation source with Main is mastered, and finally the correction method of the infrared radiation characteristics of the side jet of the aircraft model in a wind tunnel environment suitable for the model of this paper and the boundary conditions is obtained.