物理隔离网闸技术是一种越来越受到重视的安全技术。文章首先分析了现有网闸产品实现的局限性，然后针对其在依赖硬件技术和只针对特定应用的限制提出了一种改进的安全隔离网闸的实现方法。避免了硬件技术的可用性和寿命时间的限制，提高了可扩展性并且节约了成本。关键词：安全隔离网闸；开关控制；物理隔离模块；协议分析模块Abstract: The technology of Physical Isolation (Air Gap) is taken increasingimportance to the network security. First this paper analyzes the limitation of thecurrent realization. And then it brings forward an improved implementation on theGAP, which is based on the limitation of the current technique of the hardware andthe application. It avoids the restriction of the application and the time limit.Furthermore it improves the expansibility and saves the cost.Keyword: Security GAP; Switch control; Physical isolation gap module; Protocolanalyze module