Abstract: The grounding device is corroded to varying degrees every year when lightning occurs. The corrosion changes the grounding resistance value of buildings and devices,resulting in potential safety hazards. Once struck by lightning,high residual voltage is generated when strong electricity flows to the ground,affecting the safety of people and equipment nearby. In order to understand the impact of lightning current on grounding network and grasp the data of vulnerable point of grounding device,two test models are constructed,and the data of lightning impact test and power frequency current test are used for comparative analysis respectively.According to the theoretical research and experimental data,the relationship between average corrosion velocity and time of grounding device under lightning and power current is studied. It is found that lightning current and power frequency current will promote corrosion of grounding device by electrolysis. Moreover,the corrosion effect of power current on grounding device is greater due to its long duration and large residual charge.