Abstract: The main purpose of the research was to research internal relationship of sweetpotato roots on biological traits, comprehend Regularity of formation and differentiation, and provide theoretical support for standard cultivation and new variety breeding. The combination of hydroponics in greenhouse and investigation in the field were used to research internal relationship of root traits in ten sweetpotato varieties by statistical approach. The morphological trait of seedling roots such as projected area, superficial area, average diameter and volume processed the highest contribution rate and reached 80.56% in 10 days after transplanting (DAT), and the contribution rate of roots average diameter reached up to 27.79% in 20 DAT. There were highly significant positive correlation between total fresh weight per plant root and storage weight of reciprocal 3rd node, and storage weight of reciprocal 2nd node. Significant positive correlation relationship was showed between total fresh weight per plant root and commercial storage numbers. Significant negative correlation relationship was showed between total fresh weight per plant root and storage numbers of reciprocal 2nd node. The relation coefficient between total fresh weight per plant root and storage weight of reciprocal 3rd node was the highest and reached 0.6595. There was significant negative correlation between projected area, superficial area, volume and total fresh weight per plant root in 15 DAT, but there was significant positive correlation between dry weight of seedling roots and total fresh weight per plant root in 25 DAT. The relevancy between dry weight, volume, length, average diameter of seedling roots and total fresh weight per plant root was higher. There were maybe important time node for growth and differentiation of sweetpotato roots in 10 DAT and 20 DAT. The panel length and transplanting depth influenced yield information. The direct relationship existed between biological traits of sweetpotato seedling roots and yield of storage roots after harvested.