To address the issue of environmental background radiation interference in the process of aero-engines infrared radiation characteristic test, a systematic analysis of the environmental background radiation interference sources in the engine′s infrared testing process is conducted, and the background interference source suppression method is proposed. Four types of materials with different surface characteristics are utilized as the substrate of the suppression device. The inhibiting effects of different surface characteristics and different shielding angles are verified, and an efficient suppression approach for aero-engines infrared test is determined. By building the infrared test platform of the model engine, the four materials of aluminum plate, acrylic plate, wood plate and rock wool plate are selected as the base materials for the environmental background interference suppression devices to verify the inhibiting effect at the shielding angle of 60°and 90°. Through experiments, it is found that within the mid-wave infrared spectrum of 3~5 μm, the best suppression effect is achieved when a wooden board is used as the base material for the suppression device at a shielding angle of 60°, with a suppression rate of up to 93.32%.