Aiming at the low degree of mechanization of seed potato cutting, and the existing potato cutting machines have problems such as poor seed cutting uniformity, low seed cutting efficiency and low integration of machinery, a seed potato cutting device was designed, and its key components were analyzed and designed. Through the mechanical analysis, kinematic analysis and energy analysis methods of seed potato cutting process, a mathematical model of seed energy was established, and the impact was determined. The main factors of potato cutting effect were the radius of disc knife, vertical center distance between conveying roller and disc knife, rotation speed of disc knife and rotation speed of clamping roller. Using the cutting efficiency as the evaluation index, the fourfactor fourhorizontal orthogonal test was carried out with the radius of disc knife, vertical center distance between conveying roller and disc knife, rotating speed of disc cutter shaft, and rotating speed of clamping roller shaft as test factors. Analysis of variance and range difference showed that when the radius of the disc knife was 180mm, the vertical center distance between conveying roller and disc knife was 190mm, the rotating speed of disc cutter shaft was 115r/min, and the rotating speed of clamping roller shaft was 56r/min, the seed was cut. The efficiency was 74.5kg/min, the qualified rate of seed cutting was 98.8%, and the results of comparison verification test and optimization test were basically the same, which met the seed potato cutting operation requirements.