The invention provides a potato and soil separation regulating device for a potato lifter. The potato and soil separation regulating device is characterized in that an installation plate is fixed to a side plate on one side of a rack, the downward stretching end is provided with a circular hole with the axis perpendicular to the advancing direction of the lifter, a vibration regulating device comprises a hydraulic motor, an eccentric wheel, a bearing, a connecting rod, a rocker arm, a shaft, rubber wheel carriers and rubber wheels, the output shaft of the hydraulic motor is inserted into the circular hole below the installation plate from the side, close to the rack, of the installation plate, the stretching-out end, penetrating through the circular hole in the installation plate, of the output shaft of the hydraulic motor is provided with an eccentric wheel, the two ends of the sleeve external circle are fixedly provided with a straight arm and a bent arm respectively, the combinations of the rubber wheel carriers and the rubber wheels are uniformly fixed to the shaft between the two side plates of the rack in the axis direction of the shaft through the V-shaped intersection of two straight plates, and the V-shaped opening faces upwards. Automatic regulation of potato and soil separation amplitude and frequency in the potato harvesting process is achieved, the separation efficiency is improved, the potato injuring rate is decreased, the application range is wide, and the structure is simple.