与红外定焦镜头和红外两档变焦镜头相比，红外连续变焦镜头具有连续可变的视场，可对目标进行连续的跟踪，是未来红外成像技术的发展方向。随着光学冷加工、精密机械加工、镀膜技术等工艺水平的不断进步，以及现代科技的发展要求，红外变焦镜头向高变焦比方向发展，同时还须保持良好的成像和消热差性能。概述了国外各种高变焦比中波红外镜头的结构和设计方法，包括20×高变焦比中波红外镜头、30×高变焦比中波红外镜头、300×高变焦比中波红外镜头，总结了一套高变焦比中波红外镜头设计经验，对国内高变焦比中波红外镜头的应用发展研究有借鉴价值。

Compared with the infrared fixed focal length lens and infrared dual-zoom lens, infrared zoom lens which has continuous variational field of view can track targets sequentially, so it is a research direction in infrared imaging technology. With the development of optical process, mechanism process, optical film coating, it is needed for infrared zoom lens not only has high ratio, but also has good athermalized and imaging performance. The configuration and design method of foreign MWIR lens with high ratio including MWIR lens with 20× ratio, MWIR lens with 30× ratio, MWIR lens with 300× ratio were presented. A set of design experience for MWIR lens with high ratio was summarized, which is useful for the application and development of chinese MWIR lens with high ratio.