The rapid charging behavior of electric vehicles will have a huge impact on the power grid. It is of great significance to investigate the fast charge of electric vehicles on the safety risk of power grids. Considering the impact of electric vehicle access on the power grid, a multi-faceted risk indicator system is established to establish three-dimensional risk indicators. Information fusion is performed through K-L transformation, and a comprehensive evaluation method of nodal importance based on multi-attribute decision-making is used to evaluate comprehensively. The comprehensive risk ranking of the grid under the share of electric vehicles is got. The results of the study show that through comprehensive risk assessment methods, excluding the economic benefits brought by electric vehicles, electric vehicles will become more and more dangerous with the increase in occupancy rate; when electric vehicles are considered after the economic benefits, the risk of the power grid will be relatively larger in a certain interval, which has a certain guiding significance for the number of fast-charged vehicles in a certain area. This work is supported by National Natural Science Foundation of China (No. E070403).