With the implementation of the “Thirteenth FiveYear” development plan of potato processing industry and the promotion of “main food” strategy of potato, the planting area of Chinese potato is getting larger and larger;the shape difference of potato or seed potato before potato planting is different for potato production. It has important influences, and it needs to be accurately screened by grading equipment to classify seed potatoes and potatoes of similar size for the same number of cuts;and quality grading of potatoes is also a necessary step before processing exports. However, most of the potato grading methods in China use traditional manual grading, which not only has high labor intensity, but also has low work efficiency. At present, potato grading machinery in China mostly uses the general equipment of fruit and vegetable products, and the grading equipment for potato is less, which can not meet demand for potato processing and export in China. Aiming at the problems of low grades and poor classification efficiency of the existing potato grading machines in China, a new roller potato grading machine was designed. The working principle of the machine was explained. The key components were designed by theoretical calculation, and the structural parameters of the grading device were determined. The force analysis of the potato movement process was carried out to determine the factors affecting the classification efficiency and classification accuracy of the potato grading machine. The potato grading machine was analyzed by Adams simulation software. The performance was simulated and the displacement curve of the potato was obtained, which was consistent with the structural theory. Taking the feeding amount of potato, the rotation speed of the roller and the lifting angle of the lifting device as the test factors, the bench test was carried out with the classification accuracy and classification efficiency of potato classifier. The test results showed that the potato feeding amount was 55t/h. When the roller advance speed was 120r/min and the lifting angle was 24°, the classification accuracy was 96%, and the extension efficiency was 53.7t/h, which met the operation requirements of potato grading machine. It provided a good foundation for the design and optimization of potato grading devices.