The invention discloses a height auto-control type lifting, conveying and loading device of a potato combined harvester. The height auto-control type lifting, conveying and loading device comprises a foldable four-level lifting and conveying mechanism, wherein an ultrasonic height sensor is arranged at a discharging hopper at the upper end, and a control unit controls the height between the discharging hopper and a material-receiving vehicle according to information of the height between the discharging hopper and the material-receiving vehicle, detected by the ultrasonic height sensor. According to the invention, real-time monitoring of the height of potato tubers during lowering when potatoes are harvested is realized, the damage of the potatoes during the lifting, conveying and loading operations of a potato combined harvester can be effectively reduced, the intensity of operation carried out by a tractor driver is reduced, the production efficiency is high, and the maneuverability is good.