During supersonic flight, the heat radiation of aero-craft optical window has negative effect on infrared imaging performance. A computational model of radiance transmit route and radiation intensity was built in the paper. And the paper also gave the radiation emission model and infrared imaging model. The problem of heat radiance imaging was transform to the problem of optical computation. The simulation results showed that method proposed by the paper was effective to analysis the heat window radiation problem. An heating sapphire window experiment is designed to validate the simulation result. By subtraction between the deduced image based on model and experiment image, it is found that average error for each pixel is about 0.45. By analysis of experiment results, the infrared image contrast degree and Signal-to-Noise was reduced to about one third of the original ones. And the NETD of infrared system with heating window rose from 52 mK to 954 mK. The heating window radiation analysis model presented by the paper can effectively estimate aero-thermal effects on mid-wave infrared imaging system. The designed experiment developed a effective way to verify imaging system performance. And it is also much meaningful for optimal infrared spectral band selection, imaging parameter adjustment and the hot dome radiation suppression to reduce the image degradation.