Abstract: Environmental problems and energy crisis have led to the rapid development of electric vehicles. The electrical and transportation characteristics of electric vehicles make them the connection point between the power and traffic systems. Electric vehicle charging stations have become important facilities which affect the stable operation of the coupled power-traffic-system. In this paper, a maximum flow-based approach is proposed to analyze the vulnerability of the coupled power-traffic systems. Based on the traffic assignment model, the power demand of EV charging stations in the traffic network is calculated; the centrality index of transmission lines is calculated based on the maximum flow theory for identifying the critical lines. In case study, we evaluate the vulnerability of the IEEE 30 bus system coupled with traffic network—by considering the normal operation and failure state of charging stations. The results show that the critical lines carry significantly more power in the event of a particular charging station failure.