In order to explore the best seedling cultivating method of sweetpotato,the influences of mulching treatment and no mulching treatments on emergence characteristics of three sweetpotato varieties( Luoshu 10,Guangshu 87,Shangshu 19) such as seedling stage,full emergence stage,seeding number,100-seedling weight,etc. were studied under the big arch shed and small arch shed conditions. The results showed that compared to the no mulching treatments in big arch shed,the seedling stage and full emergence stage of mulching treatment were 3 d and 1—2 d earlier,respectively; seedling number of mulching treatment increased by 17. 4% —35. 2%,and the 100-seedling weight decreased by 1. 9% —4. 1%. Compared to the no mulching treatments in small arch shed,seedling stage and full emergence stage of mulching treatment were 1—2 d and 1 d earlier respectively,seedling number increased by 12. 1% —31. 0%,and the weight of 100-seedling decreased by 1. 2% —4. 3%. Compared to small arch shed treatment,seedling stage and full emergence stage advanced,seedling number and 100-seedling weight increased in big arch shed. Under the same seedling raising method,the seedling stage and full emergence stage of Shangshu 19 were earlier than that of Luoshu 10,Luoshu 10 were earlier than that of Guangshu 87; seedling number of Shangshu 19 was the highest,which of Guangshu 87 was lower; 100-seedling weight of Luoshu 10 was the highest. In summary,the seedling formation period and seedling number of big arch shed treatment of three sweetpotato varieties were better than that of the small arch shed treatment,which of mulching treatments were better than that of the no mulching treatments.