The auxiliary material is often used to reduce the resistance of transmission line tower grounding grid for the limitation of the extension and vertical grounding resistance reduction measures.For the lack of unified standard guidance when grounding modules are used in the actual tower grounding project,some problems occurred in application such as blind construction and low reduction efficiency.In this paper,the common lightning protection software CDEGS is used to simulate and calculate the influencing factors when grounding module is used to reduce the resistance of transmission line tower grounding grid.First of all,simulation is carried out for the laying position and density of the grounding module in the"-"shaped grounding grid.Secondly,the efficiency of grounding module in the grounding grid is analyzed through the simulation.Then,the influence rule of soil resistivity and soil structure on the grounding module reduction efficiency is analyzed.Finally,the corresponding construction suggestions are given for the actual transmission line using grounding module to reduce the resistance.The conclusions of this paper can provide references for the lightning protection of transmission lines and the construction of the grounding grid of towers.