In 1988, Endsley defined situation awareness as "the perception of the elements in the environment within a volume of time and space, the comprehension of their meaning, and the projection of their status in the near future" [1]. Network Security Situation Awareness can integrate all reasons of security, reflect an overall network security situation dynamically, predict the development of the security situation early, make the insecurity risk and loss to minimum, and provide reliable reference bases for enhancing the network security. Therefore, network security situation awareness has become a hot topic in the field of network security [2].