In the complex combat environment, the infrared flares was used by a plane to counter the recognition and tracking of infrared imaging seekers in order to affect guidance precision of missiles. Through the analysis of main influencing factors, the effect mechanism of infrared flares on imaging missile was revealed. First, the simulation model of infrared flares, target plane and missile guidance link were established. On the basis of analyzing and summarizing the main influencing factors of infrared flares, the effects of infrared flares launch distance, seeker target recognition time and launch interval of multiple flares were evaluated respectively. The sumulation results of the influence of various factors on the guidance and seeker systems were proposed. The influence mechanism and discipline of infrared flares on infrared imaging missiles were summarized and analyzed.