The utility model discloses a locking device of hoist and mount insulator relates to power repair tool technical field, it includes support, jib and tongs, the support includes support body, cradlingpiece, bracket aperture and support inner chamber, the jib includes pole setting, first dog, second dog, handle, spring, ring and connecting rod, it draws together the tongs body, changes hole A and changes hole B to grab handbag, it sets up the upper end at the tongs body to change hole A, it sets up the upper portion at the tongs body to change hole B, the tongs body rotates and sliding fit withthe ring through changeing hole A, and the tongs body rotates and sliding fit with the cradling piece through changeing hole B, the jib makes progress for the support or downward sliding fit, and thetongs correspondingly contracts or extend the cooperation, it has realized quick replacement insulator chain through support, jib and tongs, insulator chain and lifting device binding process laboursaving and time saving, and operating efficiency is high, and the fortune dimension is with low costs.