The invention discloses an electric power system vulnerability assessment method, and relates to the field of a power network safety analysis technology. The electric power system frangibility assessment method comprises the following steps: (1), establishing a complex network structure of an electric power system; (2), establishing a structure vulnerability factor indicator through electrical betweenness in the complex networks structure; (3), obtaining network real-time trend data through a static energy function method; (4), calculating a state vulnerability factor, and calculating to obtain an integrated vulnerability assessment indicator through combination with a structural vulnerability factor in step (2); and (5), outputting a vulnerable area of the electric power system. According to the invention, since the electric power system vulnerability assessment method analyzes vulnerable links which may exist in the electric power system from a global perspective, the vulnerable area in the operation of the electric power system can be comprehensively, accurately and effectively determined, the defects of a conventional single one-sided electric power system vulnerability assessment method and the like can be made up for, emphases are provided for prevention and control of safe operation of the electric power system, and collapse of the electric power system, caused by disturbance or accidents, is effectively prevented.