Provided is a grounding device which is used for convenient electricity testing work when power fails, and realizes firm grounding of a grounding wire. The grounding device comprises a housing, an inner core, a first arc-shaped plate, a second arc-shaped plate and a cross bar. The housing is a metal circular pipe provided with an internal thread; the outer wall of the housing is provided with a first external thread; the upper end of housing is provided with two pairs of ear plates, wherein a first oscillating bar is hinged between one pair of ear plates, and a second oscillating bar is hinged between the other pair of ear plates; the first arc-shaped plate is fixed to the free end of the first oscillating bar, and the second arc-shaped plate is fixed to the free end of the second oscillating bar; after the end surfaces of the first arc-shaped plate and the second arc-shaped plate are contacted, the first arc-shaped plate and the second arc-shaped plate form a semicircle plate; the inner cavity of the housing is provided with the inner core; and the outer wall of the inner core is provided with a second external thread matched with the internal thread. The grounding device is convenient to operate when used, and high in working efficiency, and can ensure stability of the whole body in the ground, so that the grounding wire can be firmly fixed certainly when carrying out electricity testing test after the grounding wire is installed.