Abstract: The live replacement of linear insulator strings of 500kV overhead transmission lines is a relatively common type of work in live working, which accounts for a large proportion in defect treatment. Due to the heavy load of the insulator of 500kV overhead transmission line and the heavy work tools and instruments, if the location and fixing method of the lifting point are improperly selected, it is difficult for the operators to remove and restore the connection between the insulator string and the connecting hardware, which seriously affects the operation efficiency and safety. In view of the current situation that there is no special tool available for live replacement of 500kV heavy load linear insulator string, combined with the characteristics of line equipment, this paper makes bold innovation and design on the auxiliary device for live replacement of 500kV heavy load linear insulator string, and develops special tools and instruments. Through the application of new technologies and tools, the labor intensity of operators and the safety risk of power grid can be greatly reduced, and the efficiency of defect treatment can be improved, It has certain popularization and application value.