Abstract: A comparative study was made of the removal of Th and the separation ofNp--Th by anion exchange resin cone bed and columnar bed from nitric acidsolutions. Experimantal results proved that the ratio of Th/Np was not over0.5% in product and the recovery of Np was always over 90% by cone bed orcolumnar bed under fixed conditions. Cone bed is superior to columnar bed, sincehigher recovry of Np, higher process rate and less expense of washing liquidcould be obtained with former on condition that Np--Th separation results are the--same.