Abstract: This work describes the ion exchange separation of trace amounts of uranium from large quantities of thorium and fission product elements. The fission elements were investigated including Cs, Sr, Y, Zr, Nb, Ru, Rh, La, Ce and Eu. The separation method employed Dowex1×8 as anion exchanger and Dowex50×8 as cation exchanger. U was strongly adsorbed on the Dowex1×8 resin from a medium of 8 mol/L HCl. Then washed the column by 8 mol/L HCl-0.2 mol/L NH₄F mixture. The large quantities of Th as well as other elements concerned passed into the effluent and were thus separated. U was eluted using 0.05 mol/L HNO₃. The U product contaminated pud with even equal concentration of Th can be satisfactorily purified by feeding directly to the cation exchange column and stripping using 2 mol/L HNO₃ to achieve the final purification of U from Th.