Abstract: Three reduction techniques of isotopic metal oxides，metallothermic reduction, hydrogen reduction and electrolytic reduction，were systematically studied. A plenty of isotopic metal oxides to metal isotopes by the three reducing techniques were reduced successfully, and their average reducing efficiencies are 93.1%, 98.9% and 94.2%, respectively. Finally, the purities of all reduced metals were analyzed by SEM. The results show that the purities of metals of hydrogen reduction are the best (>99%), the purities of metals of metallothermic reduction are more than 98%, but the purities of metals of electrolytic reduction are the lowest (between 92% and 97%).