针对基于隐马尔可夫(HMM)的网络风险评估中未考虑网络节点相关性的问题,结合图论,建立节点关联(NNC)状态转换矩阵,以入侵告警值(IDS)为输入,用改进的HMM模型计算出攻击路径.通过模型能进一步得到任意长度攻击序列的攻击成功率.实验结果证明,该方法简捷有效,有利于发现网络节点的脆弱性,掌握网络安全状况. Aiming at the problem that network nodes are not considered in network risk assessment based on Hidden Markov Networks (HMM), NNC state transition matrix is ​​established based on graph theory. Inputs of intrusion alarm value (IDS) The attack path is calculated by HMM model, and the attack success rate of attack sequences of any length can be further obtained through the model.The experimental results show that the method is simple and effective, which is beneficial to discover the vulnerability of network nodes and master the network security.