With the wide application of the internet and rapid development of the information technology, the scale of the internet data center power network is growing larger and larger. Some of the troubles in the internet data center (IDC) power network may cause extensive service out of service or even collapse. However, without considering the characteristics of the IDC power network, the important node identification methods for the IDC power network based on graph mainly focus on the graph structure itself. Since a large number of automatic switching equipment such as ATS, STS and loop switch have been used in IDC, when the electrical fault occurs, the load will be automatically migrated to the adjacent electrical equipment, which may lead to overloading or even tripping. So the failure is extended. So how can we efficiently and effectively capture the fault evolution mechanism of the IDC power network? How do we go about identifying the vulnerable nodes causing the collapse of the IDC power network.In this article, we propose DCPNFEM, a novel fault evolution model for the IDC power networks, as well as a fitting algorithm, BCBL, which can solve the proposed problems. Our algorithms have the following properties: (a) Intuitively: it detects fault evolution mechanism, such as power load migration, electrical equipment tripping, and so on; (b) Timely: our method is based on the real-time power loads; (c) General: our algorithms are general and practical, which can be used in various power network topologies, including data center infrastructures from tier1 to tier4.Extensive experiments on a real IDC power network demonstrate that some particular nodes’ failure can lead to the power network crash under DCPNFEM. And BCBL algorithm outperforms better accuracy and speed than many other algorithms.