The invention discloses a locking device for lifting an insulator, and relates to the technical field of electric power maintenance tools. The locking device for lifting the insulator comprises a bracket, a suspender and hand grabs; the bracket comprises a bracket body, a bracket rod, a bracket hole and a bracket inner cavity, the suspender includes a vertical rod, a first check block, a second check block, a lifting handle, a spring, a circular ring and connecting rods, and the hand grabs include hand grab bodies, rotating holes A and rotating holes B; the rotating holes A are formed in the upper ends of the hand grab bodies, and the rotating holes B are formed in the upper parts of the hand grab bodies; the hand grab bodies are rotated and slidably matched with the circular ring throughthe rotating holes A, and the hand grab bodies are rotated and slidably matched with the bracket rod through the rotating holes B; and the suspender is slidably matched upward or downward with respectto the bracket, and the hand grabs are correspondingly matched to contract or stretch; and through the bracket, the suspender and the hand grabs, the quick replacement of insulator strings is realized, the binding process of the insulator strings and lifting equipment is time-saving and labor-saving, the operation efficiency is high, and the operation and maintenance cost is low.