The utility model discloses a locking device of a power distribution cabinet. A cabinet body (1) is hinged to a cabinet door (2) at one end, a hanging plate (4) is connected to the edge of the front end surface of the cabinet body (1), a hook (3) is rotationally connected to the side of the cabinet door (2) far from the cabinet body (1), and the hook (3) is clamped in the hanging plate (4). The hanging plate (4) is of a U shape with an upward opening, two sides of the U shape are respectively equipped with installing holes (5) in the same axis, and the hanging plate (4) is connected with the front end surface of the cabinet body (1) via one of the installing holes (5). According to the above structure, the front end surface of the cabinet body is equipped with the hanging plate clamped with the hook on the cabinet door, so that the cabinet is avoided from deformation caused by the cabinet door; and thus, service life of the cabinet body is prolonged. In addition, the protruded hanging plate relatively reduces the thickness of the cabinet body, thereby saving material, and reducing cost.