The utility model discloses a ground wire clamp having a self-locking function, relates to the technical field of ground wire clamps, and solves a problem that a conventional ground wire clamp is easily jammed during ground wire assembling and disassembling processes. The main body of a U-shaped clamp body is of an inverted-U-shape structure. One side arm of the U-shaped body is hollow, and two arch-shaped conductive clamping pieces are oppositely arranged in the U-shaped area of the U-shaped clamp body. The bottoms ends of the two arch-shaped conductive clamping pieces are arranged in a U-shaped groove on the inner surface of the U-shaped clamp body, and are arranged on the opening side of the U-shaped clamp body. The top end of each arch-shaped conductive clamping piece is hinged to one end of a movable locking piece. The other ends of the two movable locking pieces are hinged to the lower end of a movable pressure bar. The top end of the movable pressure bar penetrates the top end of the U-shaped clamp body and the top end of the movable pull bar. A clamping point is arranged at the middle portion of the movable pressure bar. A spring is arranged on the outer side of the movable pull bar in a sleeving manner. The limit baffle plates are used for fixing the spring. The ground wire clamp is suitable for assembling and disassembling ground wires, especially for assembling and disassembling the ground wires of high voltage levels.