The invention provides a grounding device which comprises a magnesium-based alloy grounding body and a current conduction lead. The grounding device is characterized in that a current conduction body is fixedly installed in the magnesium-based alloy grounding body, and one end of the current conduction lead is fixedly connected with the current conduction body. The current conduction body is a copper bar. When the grounding device is used, the current conduction lead fixedly connected with the current conduction body is fixedly connected with the grounding electrode of a grounding grid, on one hand, due to the fact that the magnesium-based alloy grounding body serving as a sacrificial anode can provide a large number of electrons for the carbon steel grounding grid which is connected with the magnesium-based alloy grounding body and serves as a cathode, so that the grounding impedance of the grounding grid declines greatly, the resistance value of the grounding grid declines by 2-4 times and is stable for a long time, and the service life of the grounding grid is prolonged; on the other hand, due to the fact that the current conduction body is the copper bar arranged in the magnesium-based alloy grounding body, the specific resistance of the current conduction body is low, the current conduction body is resistant to 50KA lightning current and guides and releases the lightning current rapidly, the corrosion resistance of the grounding device is improved, the service life of the grounding device is prolonged, and the service life can reach 50 years. The grounding device is simple in structure, can avoid lightning troubles, and guarantees safety.