Abstract: Reducing the damage caused by lightning to transmission facilities and reducing the impact grounding resistance of grounding conductors are of top priority to the grounding design.The selection of different grounding conductor distribution shapes has a great influence on the lightning protection characteristics of towers. This paper simulates two kinds of radial earthing through CDEGS,and compares their impact characteristics. It is found that the standard radial earthing is more suitable for low soil resistivity area,while it is better to install herringbone earthing conductor in areas with high soil resistivity. It further applies "dendritic" short conductor to two kinds of radial grounding conductors,analyzes and compares the resistance reduction effect of the supplementing "dendritic" short conductor,which is found to have better effects with the radial earthing. After the simulation with ATP-EMTP considering the influence of spark effect,it is found that when the conductor material length is the same,the effect of applying two dendritic short conductors on a single grounding conductor is the best. The research results can provide theoretical support and analytical thinking for the selection when designing tower grounding for line towers.