Abstract: In urban rail transit, longitudinal structural steel bars in the tunnel wall are usually welded and multiple parallel structural steel bars are connected horizontally to increase the electrical continuity of the traction system. The welding process of tunnel structural steel bars is complex and the number is huge, and the effectiveness of its electrical connection engineering treatment method is a concern for the economic construction and stray current protection of metro system. This paper takes the reinforcement network models of tunnel structures with different floors as the research object, and studies the electrical conduction characteristics of structural reinforcement of metro tunnel under various working conditions, such as the number of reinforcement connection points, the overall resistance and partial resistance changes. The results show that when the resistance of the connection point is the same as the steel bar, the total resistance of the network under different layers conforms to the parallel connection law of the circuit. And the change in the number of connection points has no effect on the network resistance. When the overall number and resistance of connection points change and are greater than the steel bar, the network resistance is linearly positively correlated with the resistance and number of connection points. When the resistance of n connection points in the m-layer network changes, if there are connection points on a certain layer k, and those are always adjacent to the changing connection points in the layer k－1 and layer k+1, then the change in connection point resistance will have a significant impact on the network resistance. If at least one layer in a multi-layer network can provide a complete path for current, the impact of resistance changes at the connection point on the network resistance is within a relatively limited range.