Network security is an important foundation for the construction of digital China. With the continuous innovation and in-depth application of new generation information technologies such as cloud computing, Internet of Things and artificial intelligence, more and more data are migrating to the cloud, and the network security of cloud computing has become a new research hotspot. By analyzing the characteristics and security threats of key technologies such as big data, distributed system and virtualization of cloud computing, the network security management path is optimized from five aspects of physics and environment, network and communication, application and data, equipment and computing, and security management under cloud computer environment so as to provides users with multi-angle and all-round security reference schemes. It also provides a certain reference for the research of network security technology of cloud computing.