The invention discloses an automatic metal surface treatment device which comprises a left vertical plate, a right vertical plate, a beam plate, a carrier plate, a base plate, a clamp base, a pressing-down mechanism and an abrasive belt. The left vertical plate and the right vertical plate are arranged in parallel. The beam plate is in bridging connection with the left vertical plate and the rightvertical plate. An output shaft of a motor is provided with a driving wheel, the driving wheel is in transmission connection with a driving auxiliary wheel through a belt, an air cylinder is vertically installed on the front surface of an installation plate, a piston rod of the air cylinder is fixedly connected with a pressing-down plate, a middle shaft is sleeved with a left fixing ring and a right fixing ring from the two ends of a supporting sleeve, the left fixing ring and the right fixing ring make close contact with the two end faces of the supporting sleeve correspondingly, and the supporting sleeve is sleeved with a circular pipe which is fixed through the left fixing ring and the right fixing ring. Straight wiredrawing operation of the metal surface can be automatically achieved,wiredrawing straightness, wire flow uniformity and wiredrawing efficiency are improved, the wiredrawing quality of the metal circular pipe is ensured, and the rate of finished products is improved.