To conduct a systematic spectral radiation characteristic test of ground targets, the accuracy of the spectral radiometer must be simultaneously determined. The principle of the ground target infrared radiation characteristic test, spectral data calibration, target test, and atmospheric transmittance test method based on a spectral radiometer are introduced in this study. Using the infrared radiation characteristic test of an aeroengine based on a spectral radiometer as an example, the test scheme design, implementation process, results, and analysis are described in detail. The experimental data demonstrated the feasibility and accuracy of the method described in this study. The infrared radiation characteristic test method for aeroengines can be applied to testing and evaluation of other types of ground targets and supporting research on the infrared spectral and stealth characteristics of ground targets.