LNG具有易燃、易爆、体积易膨胀的特性，为了减少LNG事故，提高LNG球阀的安全性，有必要对其提出更严格的密封性能要求。结合目前LNG球阀常用的传统密封形式的现状及不足，重点分析了唇式密封的基本结构和密封原理，提出了唇式密封在LNG球阀中阀杆、阀座、体盖等部位的应用，以及利用唇式密封实现球阀活塞效应阀座的方法。唇式密封的使用不仅增强了球阀中阀杆、阀座、体盖等部位的密封效果，还实现了LNG气化后超压泄放的功能，保证系统安全运行，为未来唇式密封在LNG球阀中的研究和应用提供参考。

LNG has such properties as flammable, explosive and thermal expansion. In order to reduce the risk of accidents and improve the safety of ball valves used in LNG service, more stringent sealing requirements should be applied. By combining the current application and deficiencies of traditional sealing structures of LNG ball valves, this paper analyses the basic structures and sealing mechanism of lip seal, and proposes the application of lip seal in the stem, seat, body, bonnet and other structures of LNG ball valves. Furthermore, the application of lip seal to achieve piston effect of valve seats is also introduced. The use of lip seal not only improves the sealing effect of the stem, seat, body, bonnet and other structures, but also achieves the overpressure relief of gasified LNG. Thus ensures the safe operation of the system and provides reference for the further study and application of lip seal in LNG ball valves.