The temperature field of solid wall and tail jet gas on the test bench changes under different conditions of sunlight, which directly affects the infrared radiation test results of the aeroengine. Using the infrared radiation characteristics evaluation software with independent intellectual property rights, the influence of different sunlight conditions on the infrared radiation characteristics of aeroengine is analyzed, the influence law of sunlight on the infrared radiation characteristics of engines at different dates and times is derived, and the date and time suitable for the test of infrared radiation characteristics of aeroengine are given. The conclusion can provide reference for the design of aeroengine infrared radiation test.