In the existing action distance model of the infrared system,the influence factors are not thoroughly considered.Moreover,it is difficult to accurately evaluate the detection ability of the system and the infrared stealth effect of the target.Therefore, to address these issues,the action distance model and an application case analysis of the air-based infrared system were presented in this work.Based on the analysis of the influencing factors of the typical working distance of the infrared system, the implicit function of the atmospheric spectral transmittance and the working distance were defined. The distribution model of the spectral radiation intensity was clarified based on the temperature difference between the vertical layers of the atmosphere.The weighted correction coefficient of the atmospheric transmittance was deduced, considering the characteristics of the infrared spectral radiation line of the target.Next, the model of the distance between the air-based infrared system and the point target was built, which included the characteristics of the target spectral radiation, the atmospheric temperature, and the height of the infrared system. Based on this model, the detection capability of different types of air-based infrared systems and the infrared stealth performance of different types of targets were compared and analyzed. The results show that for aircraft and missile targets, the design of a large-aperture long-wave infrared system is helpful in enhancing the detection ability of the air-based infrared system regarding the head-on direction of the target.Furthermore, the large-aperture mid-wave infrared system has a stronger detection ability regardingthe rear direction of the target.The infrared stealth and penetration ability of a small-size, low-surface-emissivity, and low-speed flying target is better.Finally, the stealth performance of a target in the stratosphere is better than that of a target in the troposphere and that of a middle-layer flying target.