In order to solve the problem of power frequency arc caused by lightning strike, the author studies a multi-break arc lightning clearance which can quickly extinguish power frequency arc. In this paper, the principle of multi-fracture arc extinguishing gap arc extinguishing is introduced briefly, the magnetic fluid equation of air-coupled arc is established, the two-dimensional simulation model of arc is determined, and the high-speed air flow coupling arc process is simulated by Comsol Multiphysics multi-physical field simulation software. Simulation and experimental results show that multi-fracture arc-extinguishing clearance energy. Sufficient to extinguish the arc completely within 300us, and the air flow can cut off the energy supply of subsequent power frequency arc channel and prevent the re-combustion of the arc. The actual operation results show that the multi-fracture arc extinguishing lightning protection gap has been successfully protected against many huge lightning strikes, and no tripping accident has occurred in the normal operation of the line.