The invention proposes a locking grounding wire chuck. A connection groove is connected and fixed at the top of one side of a sliding device by a bolt, a fixed pincers mouth is connected with the connection groove by a pin shaft, a moving pincer mouth and a connection seat are connected with opposite sides of the fixed pincers mouth, a locking device is arranged at a lower part of the other side of the sliding device, the locking device drives the moving pincers mouth to clamp a power wire, a connector is arranged at a lower part of the locking device, a pin shaft transversely penetrates through the connector and is connected with an insulation operation rod, and the insulation operation rod is used for controlling clamping and separation of the moving pincers mouth. A rack and a gear in the sliding device are used for transmission, and the locking grounding wire chuck is stable and reliable to move; the insulation operation rods acts on a torsional spring at an outer side of a pawl shaft and an unhook top plate, so that a pawl is separated from a driving rack and is rapidly disassembled; a connection grounding wire clamping plate is carried at an outer side of the locking device,and connection of a grounding wire is facilitated; the clamping force is improved by a compression spring with certain pressure at an outer side of the moving pincers mouth; and the locking groundingwire chuck is suitably used a power wire connection grounding wire chuck.