Abstract: The fire water flow and quantity of 220kV outdoor substation is calculated, and the related parameters of fire pump and fire pool are determined. Through the comparison of fire pump layout and the optimization of pump house design, it is considered that the use of axial flow deep well fire pump and the combination of deluge valve and fire pump layout can reduce the area of fire fighting system and civil cost, and facilitate the operation and maintenance of the system. The fire pump and its supporting instruments should be reliable, fire pipe network should be slowly increased pressure, and adjusting the station current protection time or the fire pump configuration could be ensured that the station transformer does not trip when the fire pump starts.