Abstract: For infrared imaging meeting the development needs of high-speed aircraft, a target detection method under the condition of high heat dome infrared radiation was proposed. Firstly, the current small target detection method used in current engineering application and its flaws was described when facing aero-thermal effect during high speed fly. Then infrared radiation characteristics of heat dome were analyzed in aspect of the energy intensity distribution, the target contrast, target gray and edge changes. According to radiation characteristics and features, target detection method was proposed based on the gradient domain saliency. And the detail processes was given in the paper;finally, target contrast after background suppressing, running time, detection rate, etc. were compared between the proposed method and the commonly used small target detection algorithms. The experiments showed that the proposed method performs superiority under the conditions of thermal radiation target detection.