Abstract: In order to measure network security comprehensively, technique for order preference by similarity to an ideal solution (TOPSIS) was chosen as a comprehensive evaluation method of network security metrics to quickly detect network attacks and measure their risks, and the network security was divided into three dimensions by analytic hierarchy process, namely, environmental safety, reliability security and vulnerability security. According to the three dimensions, the network security was divided, and the metrics of each dimension were extracted and quantified. In the dimension of environment security, the evaluation value of the network security was presented based on the measurement of the network infrastructure and basic data. In the dimension of reliability security, the network was abstracted as a graph, and the reliability safety index was calculated based on the complex network theory and graph theory. In the dimension of vulnerability security, the vulnerabilities in the network were scanned with tools, and the vulnerability security index was calculated. The experimental results show that the model can improve accuracy and real-time performance in network security metrics. It is important to locate the network security risks and enhance the safety of network in time and accurately.