GIS booster station of power plant is usually connected with outdoor field by long pipeline due to site limitation，and breakdown accidents of GIS internal parts usually happen when the breaker is disconnected due to lightning strike． Taking the lightning surge fault in a hydropower plant as analyzing object，the lightning surge analysis model of booster station is established with the electromagnetic transient analysis software ATP － EMTP． The lightning surge overvoltage under the condition of breaker disconnection is calculated quantitatively，and the cause of lightning surge fault is pointed out． Effectiveness analysis of adding lightning arrester for the plant and installing line arrester are carried out，and it is pointed out that the conventional lightning protection methods could not solve the problem of the prevention and control of lightning invasion wave in hydropower GIS station． A design idea of blocking reactor for lightning invasion wave is presented，the distributed parameter model of the reactor is established，and the effectiveness of the proposed protection measures against lightning is verified by simulation． The proposed idea of lightning protection has an important reference value for lightning protection of GIS booster station in hydropower station in lightning prone area．