The invention discloses an improved potato harvester comprising a rack and a transmission mechanism, wherein a gearbox connected with a walking tractor gear box is arranged on the upper head end of the rack; a sliding gear and a clutch claw nest are arranged in the gearbox; the sliding gear is sheathed on a spline shaft through a powder metallurgy sliding sleeve; the clutch claw nest is sheathed on the spline shaft through a spring and steel balls; a clutch handle arranged on the gearbox is matched with the clutch claw nest; a fixed underframe is arranged below the rack; a steel bar sieve is arranged on the fixed underframe; a plough shovel is arranged on the front end of the fixed underframe, and vibrating grate bars are arranged on the back end of the fixed underframe; a cam and a bevel gear corresponding to the transmission mechanism are respectively arranged on both ends of a wheel-dialing shaft arranged at the rear of the fixed underframe; the transmission mechanism is connected with the gearbox through a spindle; and a dialing wheel corresponding to a plate-type chain for transmitting the steel bar sieve is arranged on the wheel-dialing shaft. The improved potato harvester is associatively connected with the gearbox of a 121 series walking tractor to realize the harvest of potatoes.