The invention discloses a special-purposed dismounting tool for a rusty closed pin of an insulator of a power transmission line. The tool comprises an insulated holding rod, an electric energy heatingdevice, a heating block and a collision block, a heating cavity is arranged in the top of the insulated holding rod along the axial direction, the electric energy heating device is arranged in the bottom of the heating cavity, and the heating block is fixedly arranged in the top of the insulated holding rod; the electric energy heating device is arranged in the insulated holding rod, and comprises a storage battery, an inverter, a to-be-heated body, a switch and a conductive coil, the storage battery is connected with the inverter via the switch, the output end of the inverter is connected with the conductive coil in series, and conductive coil is arranged around the to-be-heated body in a closed loop way; and the lower end of the heating block is fixedly connected with the to-be-heated body, and one side of the heating block is fixedly connected with the collision block.