In order to explore the impact of subsequent return stroke (SRS) on the counterattack trip rate of 500 kV transmission line, this paper calculates the number of SRS and the distribution law of lightning current amplitude. Then, the influence of the first return stroke with and without SRS, and the number of SRS and lightning current amplitude on the line counterattack trip are analyzed by combination weighting method. According to the influence proportion of these factors, it is determined that the number of SRS is the main influencing factor of line counterattack tripping. According to the analysis results of combination weighting method, this paper proposes a counterattack flashover model considering SRS, and analyzes the impact of SRS on the level of lightning resistance of counterattack through ATP-EMTP model. The simulation results show that when the line does not trip under the first return stroke, the lightning withstand level of the line considering SRS will be reduced. The reduction degree is related to the power frequency voltage period of the conductor, and the average lightning withstand level of the original counterattack is reduced by 36.4%. The simulation results are consistent with the theoretical analysis results, which can provide effective theoretical support for transmission line operation and maintenance and lightning protection design.