Abstract: Potato is one of the important cash crops in China, which needs seedling killing before harvesting. In order to improve cutting efficiency and reduce labor intensity and cost, designed a potato seedling killing and cutting device. In order to obtain the best structural parameters of the cutting device, the cutter edge angle, cutting height and cutting clearance are selected as control factors,and the maximum shear stress of seedlings during cutting is taken as index. The L₉（3~4） standard orthogonal table is used to customize the test scheme. The explicit dynamic simulation of the cutting process is carried out based on ANSYS Workbench/Ls-Dyna, and the range analysis and variance analysis of the test results are carried out. The results show that the cutting edge angle has a significant effect on the maximum shear stress, while the cutting clearance has a certain effect on the maximum shear stress, but the cutting height has no effect. The optimum structural parameters of the cutting device are the cutting edge angle of 15° and the cutting clearance of 1 mm.