The invention relates to a full-automatic grinding machine applied to a metal surface machining assembly line. The full-automatic grinding machine comprises an assembly line table top, a grinding table and the like, and is characterized by further comprising a guide rail installing base, a rotating arm, a rotating shaft, a rotating arm controller, a suction hole, a small vacuum suction cup, a vacuum generator, a guide rail, a rotation motor, a controller and a counter; and a conveying belt is arranged above the assembly line table top, the grinding table is arranged on one side of the conveying belt, and the grinding table is provided with the suction hole. A workpiece is fixed through the vacuum generator and the suction hole, and a clamp is prevented from damaging the workpiece. The rotating arm controller can control the rotation motor to enable the rotating arm to rotate, the workpiece is sucked through the small vacuum suction cup, automatic feeding and discharging are achieved, labor is saved, and efficiency is improved. The controller controls a grinding wheel installing base to move on the guide rail, manual operation is not needed, and labor is saved. After one-time machining, the controller triggers the counter to carry out one-time counting, automatic counting of the counter is achieved, and counting is more accurate.