The utility model relates to an earthing leading out device, specifically relates to a subway grounding net earthing leading out device, and solves the problem that the existing grounding net outlet line cannot achieve the requirement of stray current protection, groundwater is easy to effuse from a ground outgoing line, and the requirement of subway design cannot be met. The subway grounding net earthing leading out device comprises a wall through pipe and a ground outgoing line, and a bottom plate waterproof layer arranged between a space enclosing structure or a cushion layer and a structure bottom plate, wherein a water-resistant reinforcement layer and a polysulfide sealant are arranged between the periphery ring of the wall through pipe and the upper surface of the bottom plate waterproof layer, the wall through pipe is externally provided with a water-expansible sealing rod and a sealing flange which are positioned in a structure bottom plate and positioned above the water-resistant reinforcement layer; and the water-resistant reinforcement layer is fixed with the wall through pipe through a ferrule. The subway grounding net earthing leading out device provided by the utility model has the advantages that the structure is simple, the design is reasonable, the subway grounding net earthing leading out device can play a role of a ground outgoing line and also play the role of preventing leakage of ground water, the requirement of stray current protection is achieved, and the subway grounding net earthing leading out device can be widely applied to a subway station integrated ground net.