The invention discloses a hardware bar rust removal device. An air cylinder is arranged, a sliding rail and two sliding blocks are arranged at the bottom end of a piston rod of the air cylinder, and then fixing plates are arranged at the bottom ends of the sliding blocks, so that the fixing plates move in the direction of the sliding rail under the driving of the sliding blocks; at the same time,screw holes are formed in the fixing plate and then locking nuts are arranged, so that a hardware bar is fastened between the two fixing plates by the two locking nuts, and then the air cylinder drives the hardware bar to move up and down conveniently; then compression springs and steel wire brushes are arranged in a rust removal box, so that the compression springs compress the steel wire brushesto extrude toward the middle, the air cylinder drives the hardware bar to move up and down conveniently, and the hardware bar is subjected to preliminary rust removal by the steel wire brushes; thena rust removing liquid box is arranged, the hardware bar is driven to stretch into the rust removing liquid box by the air cylinder, and remaining rust on the hardware bar can be removed by the rust removing liquid; and at the same time, heating pipes are arranged in the rust removing liquid box, so that the rust removal efficiency is improved by heating.