The invention relates to a high-voltage cable head grounding device which comprises a grounding rod and a grounding seat. A bolt component is arranged on the grounding seat, an upper connecting ring is arranged at the top end of the grounding rod, a lower slider is arranged on the grounding rod, a connecting hole is formed between the upper connecting ring and the lower slider, and an adjusting component is arranged on the grounding seat. The high-voltage cable head grounding device has the advantages that the grounding device is directly arranged on a high-voltage cable head through a connecting column, grounding protection of operators can be achieved when wires on the cable head are disassembled by the operators, working safety is ensured, falling off of the grounding device can be prevented, the grounding device can be rapidly and fixedly mounted, a grounding wire is connected on the grounding seat through the bolt component, so that the grounding wire is fastened through the bolt component, the grounding device is firm to mount and simple and convenient to operate, the adjusting component adjusts the lower slider to move on the grounding rod, and the size of the connecting hole between the upper connecting ring and the lower slider is adjusted, so that the connecting hole adapts different sizes of wires or electric conductor and high in universality.