Abstract: In order to identify anti-jamming performance of the infrared missile, the infrared countermeasure environment need to be quantitatively evaluated. However, most of the current models analyzed the missile's anti-jamming performance from the terminal miss distance, couldn't reflect the response of each module of the missile in the process of being interfered. Therefore, based on the missile seeker system and the guidance control system in the process of jamming, a quantitative modeling method of infrared countermeasure environment was proposed. Firstly, the infrared countermeasure elements model was constructed from the scene composition and physical characteristics. Secondly, based on the influence of the countermeasure elements on the image recognition and the guidance control system, the indicators of similarity, masking degree, jamming time, target maneuver and entry angle were proposed. Finally, by using parallel relation model, geometric mean synthesis model and weighted sum model, the total environmental complexity quantification model was established based on the above indicators. Simulation experiments show that the probability of the missile hit ratio error within±6% predicted by this model is 95% in typical countermeasure scenarios.