The invention discloses a thread-off proof device for line hardware, and the device comprises a preposed body and a postposed body, which cooperate with a ball socket. The preposed body and the postposed body are reliably fixed through a fastening part, and form a cavity which can be tightly attached to the peripheral surface of the ball socket in a sleeving fit manner through enclosing. The center of the top of the preposed body is provided with a gap which adapts to the ball socket. In use, the preposed body and the postposed body are reliably assembled through the fastening part, and the preposed body and the postposed body are respectively attached to the exterior and rear part of the ball socket, thereby effectively guaranteeing the structural reliability of the ball socket and a bulb in the subsequent use process of power transmission and transformation equipment, protecting the ball socket and the bulb from being damaged and falling under the severe conditions of strong wind, and guaranteeing the reliable and stable operation of a transmission and transformation line. In addition, the gap can guarantee that a bend can move freely when the equipment is in operation, and avoids the structural interference between the device and the ball socket.