Abstract: China is a big country of sweet potato planting，and automatic harvesting machine plays an important role.Sweet potato transportation and separation mechanism is an important mechanism in sweet potato harvester，which has a crucial impact on rate of damaged and exposed potatoes.Through discrete element simulation，impact damage and soil fragmentation effect of sweet potato were analyzed，and optimal parameters were obtained.According to this，design and manufacture of prototype was carried out，and field test was carried out to verify simulation results.According to the TRIZ theory，innovative design of classification collection mechanism was carried out to solve problem of poor classification efficiency.