Transmission line towers are prone to lightning strikes.When the grounding resistance of a tower is too high，the fault rate of the line is increased.To effectively reduce the lightning impulse grounding resistance of typical grounding devices and guide the grounding design of transmission line towers，a composite grounding device consisting of a typical tower foundation combined with a claw-shaped grounding body is proposed.A model of the claw-shaped grounding device is established using CDEGS software，and its time-domain impulse response characteristics are analyzed while considering the soil spark effect.Quantitative comparisons of the impulse grounding resistance of the claw-shaped grounding device are conducted under different lightning current amplitudes，soil resistivities，claw-shaped grounding electrode connection locations，and grounding electrode burial depths.The results show that under the same environmental conditions and material lengths，the claw-shaped grounding device improves the lightning impulse grounding performance by 17.23% and 18.35% compared with vertical extended grounding and horizontal extended grounding，respectively.While further reducing the impulse grounding resistance of the grounding device，the installation difficulty of the grounding device is also reduced.