The invention provides a device for replacing an insulator. The device comprises a support connection rod, locking devices which are symmetrically arranged at two ends of the support connection rod, a traction device which tightens the two locking devices, and a cross connection frame which prevents the rolling of the whole device. The locking devices are fixedly connected to the support connection rod through hanging hole plates. One end of each of the hanging plates is fixedly connected to the support connection rod, and the other end is fixedly connected to the locking devices. The two locking devices go across a rod porcelain needed to be replaced and are locked at the steel caps adjacent to the rod porcelain. The traction device retracts such that the two locking devices retract, thus the rod porcelain needed to be replaced is slack, and the disassembly is carried out. Hang hooks are hanged in adjacent fixtures, the rollover of the whole device is prevented, device has the advantages of convenience and labor saving, the high-altitude operation amount and working strength are reduced, and the replacement time of the insulator rod porcelain is reduced.