The utility model relates to a backup protection fixing -line device, including mainboard 1, win 2 in succession, single arm -drag 3 keeps silent 4 on, keep silent 5 down, the 9, the 5th round pin axle 10 on first round pin axle 6, second round pin axle 7, third round pin axle 8, the fourth round pin axle, insulator spindle link up with 11, pull rod 13, spring pin 14, spring pull ring 15, the spring pin sets up on the mainboard, the spring pin is not when receiving external force, and the one end of spring pin stretches into in the circular arc leads to groove 12, the terminal of spring pin is connected with the spring pull ring, the spring pull ring is used for pulling out the circular arc with the spring pin and leads to the groove. The utility model discloses set up insulating bar couple, spring pin and spring pull ring spare, can effectively protect and operate potential safety hazards such as transmission pressure tension releasing that the reason causes and slippage by multiplexer utensil or personnel, guaranteed the electrified smooth implementation of changing transmission line dead end insulator work, reduced fortune dimension intensity of labour, improved live overhaul efficiency, the operation of guarantee electric power system safe and reliable.