Naked seedling transplanting is the main planting method of sweet potato in China, which requires high mechanized transplanting. At present, the domestic sweet potato transplanting machinery is relatively lacking, the existing equipment has a low degree of automation, and most of them adopt manual seedling feeding, which leads to high labor intensity in the field and low quality of mechanized planting. Combined with the agronomic requirements of planting naked sweet potato seedling, an automatic transplanter for naked sweet potato seedlings was designed based on the pretreatment seedling belt feeding device and the flexible disc planting device, According to the requirement of automatic operation control of feeding device, flexible disc planting device and watering device of sweet potato bare seedling transplanter, a control system of sweet potato bare seedling automatic transplanter based on CAN bus was designed, which can complete rotary tillage, ridging, ditching, automatic and orderly seedling feeding, planting at fixed plant distance, pressing soil covering, automatic watering, ridge repairing and other operations at one time. Field experiments showed that when the distance of target plant spacing was 25cm and the working speed was 0.25m/s, 0.35m/s and 0.45m/s, the coefficient of variation of planting plant spacing and the qualified rate of planting depth all met the standard requirements, the variation coefficient of plant spacing and the qualified rate of planting posture were affected by the working speed greatly, but the planting depth was less affected by the working speed. When the working speed was 0.25m/s, the working performance index was better than 0.35m/s and 0.45m/s. The average variation coefficient of plant spacing was 10.16%, the average qualified rate of planting depth was 95.56%, and the average qualified rate of planting posture was 90%. The research result can provide a reference for the theoretical research and innovative design of mechanized and automatic transplanting machinery for naked sweet potato seedlings.