Hilly and mountainous areas were the main potato planting areas in China. In view of the low efficiency of mechanized harvesting and separation and picking up of potatoes in small plots, a crawler type self-propelled sorting potato harvester was designed in combination with the requirements of potato planting agronomy and harvesting. The overall structure and key components of the prototype were designed, which were mainly composed of crawler drive chassis, excavation device, automatic alignment device, separation device and sorting device. The prototype had technical advantages such as crawler driven walking, high-frequency low amplitude vibration clod crushing, automatic row excavation, manual auxiliary sorting and hydraulic drive mode. On the basis of describing the overall structure and working principle, combined with the potato kinematics model and collision characteristics analysis, the structural parameters and operating parameters of the key components were determined to achieve the goal of high efficiency and low loss harvest. The separating screen was inclined at 30°, the distance between two adjacent gear rods was 210mm, the height of the stop bar was 25mm, the maximum rotating speed of separator driving wheel was 120r/min, the maximum line speed of the sorting screen was 0.65m/s, the drop height between the end of the separating screen and the beginning of the sorting screen was 120mm. As the method of manually assisted potato sorting and gathering was adopted, the number of drops and rolls of potato blocks was reduced, the separation stroke of potatoes was shortened, and the collision frequency and damage of potatoes in unit time were reduced, which was helpful to realize the loss reduction harvest. The prototype was tested in the field. The results of the field test showed that when the operating speeds of the prototype were 1.0km/h and 1.2km/h, the running linear speeds of the separating screen were 0.61m/s and 0.72m/s, the running linear speeds of the sorting screen were 0.42m/s and 0.50m/s, and the productivity was 0.10hm2/h and 0.12hm2/h, respectively. The average value of the three peak impact acceleration of electronic potato was 51.02g and 51.85g, the peak impact acceleration of potato was less than the critical damage threshold. There was no missing inspection and skin damage of potatoes, and the effect of the harvest was good. All performance indexes met the requirements of relevant standards.