The invention discloses a grounding device of a transformer neutral point integration protection system. The device comprises a lightning arrester connection end, an upper conducting rod, an upper contact head, a lower conducting rod, a lower contact head, an insulation pull bar and a transmission mechanism. The lightning arrester connection end is installed and fixed to a tail end of a lightning arrester. One end of the upper conducting rod is hinged to the lightning arrester connection end. The upper contact head is arranged on the other end of the upper conducting rod. The lower conducting rod is provided with a chute. A slide bar is embedded in the chute. The lower contact head is installed and arranged on one end of the lower conducting rod. The other end of the lower conducting rod is installed and fixed to an installation pedestal of the lightning arrester through a lower rotation shaft. One end of the insulation pull bar is hinged to the upper conducting rod and the other end is hinged to the slide bar. The transmission mechanism is connected to the lower rotation shaft. In the invention, a grounding system structure is simplified; cost is saved and a land occupation space is reduced; a zero sequence current is tested so that a system is safe and reliable; and a power supply system can be effectively protected.