Abstract: In order to select the Th/U separation process required for gram scale 233U production, ion exchange and solvent extraction processes were developed respectively for the initial recovery of U from ThO₂ target. The solvent extraction separation employed 5% TBP dissolved in n-dodecane solution as an extractant which has high separation factor values of U(Ⅳ) over Th(Ⅳ). The ion exchange separation employed Dowex 1×8 as anion exchanger on which uranium could be strongly adsorbed whlie thorium can not. The results indicated that both the two methods were successfully applied in Th/U crude separation. The U crude product can be satisfactorily purified by the cation exchange column. Ion exchange process was selected through a comparative study of recovery of U and decontamination factor. Under the optimized condition, the recovery of U was 98.3% and the U product was contaminated with less than 0.02% of thorium and other fission product elements.