The high temperature window of a hypersonic vehicle can have a severe impact on the imaging performance of the infrared seeker. In order to quantitatively analyze the high temperature window effect, the imaging and quantitative characterization model of the infrared seeker in high temperature window was established through the coupling of the signal response characteristics of the infrared seeker and the high temperature thermal radiation characteristics. The quantiative charateriation model was verified by high temperature window experiment of typical infrared seeker system. Based on the quantitative characterization model, combined with the ship radiation data obtained from the external field test, the imaging results of the infrared seeker under various temperature windows were calculated, and the imaging performance of the infrared seeker under the high-temperature window was evaluated. The analysis results indicate that when the window temperature exceeds 250 ℃, the naked eye can hardly distinguish the ship through the image; when the window temperature exceeds 300 ℃, the target resolution and tracking cannot be achieved by the seeker recognition algorithm.