Abstract: A security situation assessment model is proposed in this paper.One of the math function and the rectification function is used to design the experience function in the theory of evidence，the theory of evidence is brought into the security situation assessment.From correlating and fusing the data which is provided by the sensors deployed in the network to depict the curve of security situation，the whole process is completed.The security situation assessment model and the algorithm are verified.The results show that the problem of network security situation assessment is resolved very well by the use of the theory of evidence.At last the method how to apply this assessment model to large-scale network security situation assessment is introduced in this paper.

Key words: security situation assessment, multi-source data, theory of evidence, rectification factor

摘要： 提出了一种安全态势评估模型。利用反正切函数和修正函数来设计证据理论中的经验函数，将证据理论引入到安全态势评估中，对部署在网络中的多种传感器设备提供的安全数据进行关联、融合，绘制安全态势曲线，给出当前网络的安全态势。对所提出的安全态势评估模型和算法进行了测试、验证。结果表明证据理论的应用很好地解决了网络安全态势评估问题。介绍了如何将这种评估模型应用到大规模网络安全态势评估中去。

关键词: 安全态势评估, 多源数据, 证据理论, 修正因子