Abstract: When processing large-scale network security events，a network security situation evaluation system can be useful and help user to deal with these security events.This paper proposes an approach that computes network security disaster index and designs a security situation evaluation system for large scale network.Using replaying network security events，this system can evaluate network security situation，compute disaster index of whole network and give a policy of processing these security events.The results of experiment illustrate that this approach is effective for evaluating large scale network security situation.

Key words: security situation evaluation, disaster index, parallel/distributed network simulation, security events

摘要： 在大规模网络安全事件应急响应过程中，一个网络安全态势评估系统可以起到很好的辅助决策作用。提出了一种计算网络安全危害指数的方法，并在这种方法基础上设计实现了一个大规模网络安全态势评估系统。该系统通过对网络安全事件的模拟重放，对网络安全状况进行评估，给出网络整体的安全危害指数，并提出针对安全事件的响应控制策略。系统运行结果表明，这种安全态势评估的方法针对大规模网络安全行为是有效的。

关键词: 安全态势评估, 危害指数, 并行网络模拟, 安全事件