Abstract: In the current hydrometallurgy processing of rare earths, the methods, such as selected precipitation (pH1.05), (liquid) extraction, or fractional precipitation-fractional crystallization, are usually ed to remove thorium. regardless of the acid or the alkaline proeess. The principle of there methods is based on the difference in partition value K between thorium and rare earths. The insufficiency of above methods in processing is that the thorium partitioned into several parts, may impair the purity of certain final individual rare earth product and environmental protection. In order to improve the removal of thorium from rare earth, the character of thorium and its behaviour on cation and anion ion exchanger are analyzed. On the basis of above analysis the cation and anion ion exchange chromatography is proposed as a new technology in rare earth hydrometallurgy processing for better removal of thoritum from rare earth.