A kind of piston rod of rock drill, including a conduit, with multiple limit chutes on the side wall of the conduit; there is an air hole in the center of the conduit, and the upper air hole communicates with the lower air hole; a sealing connector is provided at the bottom of the conduit, and the inner wall of the sealing connector is provided with internal threads; the part of the conduit with the limit chute can reciprocate in the cylinder. This invention has a simple and compact structure, stable operation, and effectively prolongs the service life of the piston. Ceramic piston rod spray gun moving device: A ceramic piston rod spray gun moving device equipped with a machine tool, including a spray gun bracket for installing the spray gun, a screw, a guide plate, a support block, a movable joint assembled and connected with the guide plate, and a power source assembled on the machine tool; the spray gun bracket is slidably assembled with the guide rail of the machine tool through the guide plate; one end of the screw is drivingly connected with the power source, and the other end is rotatably assembled with the machine tool; the movable joint is assembled on the screw. This moving device has the advantages of simple structure, small volume, and good ceramic spraying quality.