Physical grading and collecting device for potatoes in potato field

The invention discloses a physical grading and collecting device for potatoes in potato field. The device comprises: a potato guiding plate, grading rollers, a transmission chain, transmission shafts, a driving motor, a potato blocking plate, a small potato collecting box, a small potato outlet, a large potato collecting box, and a large potato outlet. The potato guide plate, the transmission shafts, and the driving motor are all mounted on the potato blocking plate; the transmission shaft is sleeved with the grading rollers, wherein the grading rollers are sequentially and horizontally fixed to the potato blocking plate at different intervals; the transmission chain meshes with the two ends of the transmission shafts; the driving motor and the transmission shaft rotate to drive the transmission chain so as to enable the grading rollers to rotate; the small potato collecting box and the large potato collecting box are arranged under the grading rollers; the small potato outlet is arranged under the small pota