Abstract: In order to analyze the electromagnetic transient characteristics of shared tower under lightning strike and the influence of different grounding schemes on the grounding reliability of sharing tower, the shunt model of 110 kV shared tower under lightning strike is established, and the influence of tower base number on the calculation results is analyzed. Then, the shunt coefficient of shared tower, transient voltage and current distribution of tower top and grounding body are calculated. Finally, the influence of grounding grid connection type, the number of grounding grid equipotential connection points and the height of communication equipment on the grounding reliability of shared tower are analyzed from the perspective of ground potential rise balance and tower lightning protection performance. The results show that before and after the tower shared, the lightning overvoltage amplitude deviation at the top of the tower and the cross arm position is small, which will not affect the lightning protection performance of the tower. When the equipotential of the base station ground network is connected to the tower ground network, the ground potential rise is significantly reduced and the potential balance is improved. When the communication equipment is located on the tower, the ground potential is well balance. The research results can provide reference for grounding scheme design of shared tower.