Abstract: In order to find the relationship between growth and development of sweetpotato root and endogenous hormone, the experiment analyzed dynamic changes for root agricultural traits and endogenous hormone by hydroponics used 1/2 Hoagland nutrient solution. The results showed that root length of ‘Yanshu25’ was always higher, and root fresh weight of Aya and ‘Jihei1’ was the highest, but its average root dry weight per plant was the lowest during 25 days after transplanting (DAT). The storage root of sweetpotato (‘Xushu18’, ‘Jixu23’) mainly used to process starch had differentiated in 10 DAT and began to accumulate dry matter. The procedure of differentiation of ‘Xushu18’ and ‘Jixu23’ was earlier than fresh sweetpotato (‘Jishu22’, ‘Yanshu25’) and purple-fleshed sweetpotato (Aya, ‘Jihei1’). It was found that endogenous hormone content of root was diversity in different cultivars at different developmental stages and different nodes. The content of growth promoting hormones such as IAA, ZR and GAs reached peak in 15 DAT, but the content of ABA was nearly the lowest in 15 DAT. After correlation between agronomic traits and endogenous hormone was analyzed, root volume of bottom node mainly related to the balance of growth promoting hormones, and grew slowly from 5 DAT to 25 DAT. The root of penultimate node antepenult node grew rapidly in 20 DAT, and dry matter accumulated speedily. The time of root differentiation form bottom node to antepenult node was respectively in 20 DAT, 15 DAT and 10 DAT. The tendency of differentiated for each node up from basic part of sweepotato seedling was gradually ahead of time. In conclusion, spatial and temporal disparities were found between root growth, differentiation and regulation of endogenous homone in different node of sweetpotato seedling root.