4U series of sweet potato harvester is mounted with the tractor of 12-60hp with back power and side power output shaft. Our tractor potato harvester is intended for potato excavation, tubers partial separation from the soil and tubers laying on field surface for their further picking up. A triangular beater is set on the potato harvester. The working principle of this potato digger is that the digging shovel digs up the soil and crops through the impetus of the tractor. And the digging shovel make crop and soil separate though vibration sieve, the soil first drip down from the clearance of vibration sieve, finally the crop crashed down on to the road from the back.