The invention discloses a high-voltage grounding wire clamp comprising a main body part and an auxiliary clamping device. The main body part comprises a conductor clamp, a rod body and a grounding wire clamp handle which are connected in turn. The auxiliary clamping device comprises a connector cap and a taper sleeve clamping component. The top part of the connector cap is provided with a through hole. The grounding wire clamp handle is inserted in the connector cap via the through hole. The grounding wire clamp handle is clamped by the taper sleeve clamping component. The conductor clamp comprises a fixed clamp sheet and a flexible clamp sheet. The top part of the rod body is provided with a driving structure which drives the flexible clamp sheet and the fixed clamp sheet to clamp. The grounding wire clamp handle rotates to drive the rod body to rotate. The flexible clamp sheet and the fixed clamp sheet are enabled to clamp or loose by the driving structure through rotation of the rod body. Installation difficulty of the grounding clamp is reduced, and torsional torque is monitored by a torque wrench to indirectly obtain the clamping situation of the conductor clamp so that reliable connection of the grounding wire clamp and a bus bar or a power transmission line can be guaranteed.