Abstract: Transmission lines are highly susceptible to transient overvoltages caused by lightning strikes, which may lead to insulation flashover and equipment damage, posing serious threats to the secure operation of power grids. To address the issues of slow response and uneven energy dispersion in traditional lightning protection measures, this paper proposes a transmission line safety protection method based on advanced lightning protection technology. By establishing a lightning traveling-wave propagation model and a line safety characteristic equation, a nonlinear energy absorption and dynamic grounding impedance adjustment mechanism is developed to achieve rapid absorption and balanced distribution of lightning energy. Finally, pilot verification conducted on a transmission line test platform demonstrates that the proposed method significantly improves lightning protection stability and transient recovery performance, providing reliable technical support for the safe operation of transmission lines.