目前网上传播的有害信息已经成为不可忽视的社会问题,它不仅毒害人们的思想,而且可能会影响社会安定,威胁国家安全。为了加强对网络信息的控制,保证网络传播内容的安全性,该文设计了一种基于内容安全的局域网监控系统。文章首先介绍了系统各组成部分及功能,然后对系统实现过程中的关键技术进行了阐述,最后列举了该系统的主要功能。实验证明,该文设计的局域网监控系统,能对内部网络进行监控和管理,有效地保证了网络上传播的内容的安全性。 At present, the harmful information disseminated online has become a social issue that can not be ignored. It not only harms people’s thinking, but also may affect social stability and threaten national security. In order to strengthen the control over the network information and ensure the security of the content disseminated by the network, this paper designs a local area network monitoring system based on content security. The article first introduces each component and function of the system, then elaborates the key technology in the process of system realization, and finally lists the main functions of the system. The experiment proves that the local area network monitoring system designed in this paper can monitor and manage the internal network and effectively ensure the security of the content disseminated on the network.