Abstract: In accordance with current problems that soil and potato are separated incompletely, potato digger are easy to be plugged, excessive power consumption and so on, exsit in potatoes digger. A disc ce-grate type potato digger was designed, which matched with the four-wheels tractor. The fense-like digging shovel device and the disc ce-grate type of separation device was used to improve the separation efficiency, and the key parameters of the fense-like digging shovel device and the disc ce-grate type separation device were calculated and determined. The disc cutter structure was improved to leave tiny soil on the two sides of digging shovel while cutting soil. Field test showed that potato digger performed smoothly in digging and transporting, the separation effect was efficient, damage rate was 4.3%, losing rate was 3.3%, the obvious rate was 97.5%, all of which matched with the design requirements of technical specifications. Besides, in comparison with field test results of poke-finger-wheel type potato digger, obvious rate and damage rate of disc ce-grate type potato digger were better. Therefore, the study can provide an anti-blocking, easily picking up, little power consumption and well-adapted potato digger for ridge potato digging in the northwest dry farming area.