Abstract: Cement used to be main material of well completion process at in-situ leaching uranium mines.Quality and efficiency of well completion were been constrained in drilling process because of complicated process and damaged permeability of ore bad.Soduium-based bentonite is a suitable material of well completion process.It reacts with water to form high strength binder which can seal between orebearing aquifer and other aquifers.Based on researching the hydrogeological condition of a uranium deposit in the south of Kazakhstan,a series of laboratory and field tests were carried out for sealing with bentonite rings in none-gravel structure wells.The results indicate that precision and reliability of well completion have been improved.Meanwhile,the quality of production wells have been imporved in a certain degree.