Abstract: The temperature of the high speed aircraft optical dome rapidly rises due to aerodynamic heating, and causes severe thermal radiation effect to detection system in the aerodynamic thermal environment. To assess the performance degradation as a result of aerodynamic heating of the dome flying at high speed, the thermal radiation transfer of the optical dome was modeled by introducing the concept of heat pupil. The thermal radiation transmission of the dome through the optical system was simulated numerically, and the irradiance distribution of the dome on the detector-s receiving surface was obtained according to the nonhomogeneous temperature distribution. The research results show that the concept of heat pupil suits for the dome and reduces the time in ray tracing enormously, and according to the trend of the dome-s radiation receiving by detector following time, we can see after a few seconds in flight the interference radiation from dome would flood the target signal. Therefore, the thermal radiation of the dome in aerodynamic thermal environment cannot be neglected.