Soil water content decrease gradually from early-successional habitats to late-successional habitats in abandoned arable land in northern mountainous region of Yuzhong County. Accordingly, late-successional species have stronger ability to resist drought stress than early-successional species. Root traits are associated with plant drought resistance, and therefore, it is proposed that root traits between early-successional species and late-successional species should differ significantly. However, relatively little effort has been focused on the investigation of root traits among successional species. The object of this study is to use simple gel chamber to compare seminal root straits in early-successional species, Artemsia annua, middle-successional species, Heteropappus altaicus, Artemisia frigida, and Leymus secalinus,and late-successional species, Stipa Breviflora. Seeds germinated on the surface of gel in petri dishes, oriented vertically so that the radicles faced downwards, at 16 ℃/8 ℃ day/night. After germination, seeds were transferred to the gel chambers, maintaining the same orientation as during germination, and allowed seminal root to grow at temperature mentioned above. Measured parameters included main root length, main root elongation rate, lateral root number, lateral root length, lateral root elongation rate, the ratio of lateral root length to main root length, angular between main and lateral roots and thousand-seed weight. The results showed that germination time for early-successional species was about 6 days, for middle-successional species ranged from 6 days to 9 days, and for late-successional species was about 14 days. After 2-week growth, early-successional specie, A. annua, had short main root, an increase in lateral root number, lateral root length and lateral root elongation rate, an increase in the ratio of lateral root length to main root length, and high angular between main and lateral roots. By contrast, late-successional species, S. Breviflora, had an increase in main root length, a decrease in lateral root number, lateral root length and lateral root elongation rate, a decrease in the ratio of lateral root length to main root elongation, and low angular between main and lateral root. The values of these traits of middle-successional species, H. altaicus, A. frigida, and L. secalinus, were between those of early-successional species and late-successional species. Thousand-seed weight had no relationship with main root length, lateral root number, total lateral root length and angular between main and lateral roots, showing seminal root traits did not dependent on seed mass. The results indicate that the transition from early- to late-successional species reflects that the priority of resource allocation in root growth shifts from enhancing of absorption of resources by lateral root in early-successional species to counteracting to dry soil in the late-successional species.