The invention discloses a hand-in-hand line centrally-positioned wire-outgoing switchgear grounding switch blocking device, system and method. The grounding switch blocking device comprises an outer cover. A side of the outer cover is provided with a protruded baffle plate. The other side of the outer cover is hinged to an installing base plate. An electromagnet is disposed on the installing base plate, is equipped with a switch button, is connected with a dead bolt, and is capable of driving the dead bolt to move. The outer cover is provided with a clamping groove. The dead bolt can be clamped to the clamping groove in order to enable the outer cover to be on the installing base plate. When a high-voltage line is powered on, the dead bolt is clamped in the clamping groove, the baffle plate blocks a centrally-positioned switchgear grounding knife switch operation port such that the grounding knife switch cannot be switched on. When the high-voltage line is powered down, the switch button is pressed in order to power on an electromagnet, the dead bolt is withdrawn and the outer cover is opened, thus, the grounding knife switch can be operated. The electrification display blocking device is reliable in contact, correct in indication, reliable in blocking, and easy to install, greatly reduces safety threat of running and overhaul workers, and achieves a target requirement.