Infrared radiation characteristics is the basis of midcourse infrared warning, detection, identification and track of high-speed aircraft. High-speed aircraft midcourse infrared radiation is closely related to surface temperature, which is related to ascent-stage aero-heating, space thermal radiation, heat-shield structure, and so on. In order to obtain high-speed aircraft’s midcourse infrared radiation in the complex environment background, it is necessary to study the influence of aero-heating, space thermal radiation, surface heat-shield radiating and structure heat conduction on the infrared radiation.Taking into account the influence of ascent-stage aero-heating, space thermal radiation, surface heat-shield radiating and structure heat conduction, making use of aerodynamic heating engineering computation model, space thermal heating computation model, and 1D multi-layer heat conduction computation method, the high-speed aircraft infrared radiation analysis technology is established, and high-speed aircraft midcourse temperature field and infrared radiation analysis is realized under the influence of aero-heating, space radiation heating, radiation heat dissipation, structure heat conduction, and so on.The computation temperature results match well with flight test results under typical working conditions (Fig.4-5), which verifies the validity of the computation model and methods. The ascent-stage aero-heating has a large effect on the midcourse surface temperature and infrared radiation (Fig.7-10). In the midcourse, the infrared radiation intensity in the wavelength range of 8-12 μm is notably larger than that of 3-5 μm. Therefore, choosing the wavelength range of 8-12 μm is more advantageous for high-speed aircraft midcourse detection (Fig.11).In order to simulate the infrared radiation of the high-speed aircraft in midcourse flight, the temperature field and infrared radiation characteristics analysis technology is developed, considering the influence of ascent-stage aero-heating and so on. The technology is validated through comparison with flight test measurements. It is found that: the ascent-stage aero-heating has a large effect on the midcourse infrared radiation. In the midcourse, the infrared radiation intensity in the wavelength range of 8-12 μm is notably larger than that of 3-5 μm. Therefore, choosing the wavelength range of 8-12 μm is more advantageous for high-speed aircraft midcourse detection.