The invention relates to an automatic polishing machine for a cylindrical product. The machine comprises a supporting plate, wherein a loading rotating seat which is connected with a loading motor below the loading rotating seat is arranged on the supporting plate; a pressing device is arranged above the loading rotating seat and is in match with the loading rotating seat through a pressing rotating seat; a polishing wheel is arranged on the side surface of the loading rotating seat; a bearing block is arranged on the supporting plate; a polishing rotating shaft which is connected with a polishing motor is arranged on the bearing block; a driving wheel is arranged on the polishing rotating shaft; a polishing sanding belt which is in match with the loading rotating seat is arranged between the driving wheel and the polishing wheel; the polishing wheel is connected with a feeding mechanism. According to the automatic polishing machine for the cylindrical product, the loading rotating seat which is driven through the loading motor is provided, the pressing device provided with the pressing rotating seat is arranged, and the movable polishing sanding belt which is in contact with the product side surface is provided, so that the continuous automatic polishing can be achieved; in addition, the polishing uniformity and accuracy can be greatly improved.