Many scholars have applied complex network based models to investigate power grid. vulnerability, but how effective are these models to capture the real performance is an interesting topic. This paper selects two typical complex network based models, including a purely topological model (PTM) and a betweenness based model (BBM), as well as a direct current power flow model (DCPFM), to simulate the topology-based and flow-based vulnerability of power grid under degree, betweenness, maximum traffic and importance based intentional attacks. The relationships of vulnerability results from different models are analyzed and discussed for model comparisons. Taking IEEE 300 power grid with line capacity set proportional to tolerant parameter tp as example, the results show that there exists a critical node attack intensity Al = 0.147, above which the three models produce almost identical topology-based vulnerability results under each attack strategy at any tp >= 1, while producing identical flow-based vulnerability results from PTM and DCPFM occurs atAl > 0.147, and Al > 0.73 for BBM and DCPFM, which indicates that the PTM can better approach the DCPFM for flow-based vulnerability analysis under intentional attacks. Similar results are also found for intentional edge attacks and other power grids. (C) 2014 Elsevier B.V. All rights reserved.