Abstract: Yemaquan section in Beishan area, Gansu Province, is one of the preselected sections of disposal repository for high level radioactive waste (HLW) in our country. Taking this section as an example, based on the measurement and analysis of ground-water U, Th content and isotopic ratio, the uranium occurrence species was calculated. The results show that the uranium occurrence species in groundwater in the area is mainly U(OH)₄(aq). The uranium migration feature was explored in this paper. The evidences show that the migration ability of uranium is very limited in the geological, hydrogeological environmental conditions of the section.