Abstract: The identification of critical lines is of great significance to ensure the safety of the power system. Most of the existing methods of critical line identification methods are not complete enoughhave a lot of shortcomings because they seldom consider the information carried by nodes and the accidental faults of lines are considered insufficiently. Therefore, a multi-index identification method for critical line identification was is proposed, based on the grid topology and the current operation modes. Firstly, by considering the voltage stability of local system, the capacity of each line, the line fault probability and the topological importance of the nodes of a local system, four evaluation indexes wereare established to identify the importance of the line including its voltage stability, capacity margin, real-time fault probability, and topological connection degree. Secondly, the comprehensive importance index with the subjective and objective weighting considering different factors wereare establishedproposed, developed by the improved method of maximizing dispersions. Meanwhile, the strategy of the least system load shedding wasis adopted to measure the power supply capacity of the power grid with the failure of the critical lines. Finally, the feasibility and correctness of the proposed identification method wereare verified via the simulation ofin the IEEE 39-bus system.