Abstract: Aiming at the problems of soil yon blockage, high loss rate and low bright potato rate in potato harvesting process, by establishing potato soil discrete element model, we focus on potato-soil movement law in the harvesting process, clarify the dynamic relationship between excavation shovel and potato agglomerate in potato harvesting process, and analyze the law of potato agglomerate fragmentation by excavation shovel under different working parameter combinations. With forward speed, operating depth and soil entry angle as test factors, working resistance and soil fragmentation rate as test indexes, experimental analysis and design, through Design-Expert optimization design, the best working parameters of excavation shovel, forward speed 0.5m/s, operating depth 170mm, soil entry angle 45°, under the best working parameters, working resistance is 1384.65N, soil fragmentation rate is 95.77N. The soil crushing rate is 95.77%, which meets the potato harvesting requirements.