Abstract: The process of Pu reductive stripping by hydroxylamine nitrate in plutonium purification cycle was optimized by the single extraction experiments. Hydrazine nitrate can reduce a small quantity of Pu(Ⅳ) and strip it from 30%TBP-kerosene into an aqueous phase, but can suppress the plutonium reductive stripping with increasing hydrazine nitrate concentration, where hydrazine nitrate plays a role as a salting-out agent. For the Pu purification cycle, the Pu recovery can be improved by enhancing the reductant flow when keep the HAN/Pu molar ratios invariable. 2.3 is feasible for the HAN/Pu molar ratios when the temperature is 50℃. Pu concentration in organic phase increases with raising the reaction temperature because reaction rate of HNO₃ with Pu(Ⅲ) is accelerated, and also increases with increasing ionic strength because the distribution coefficient of Pu(Ⅲ) is amplified due to the salting-out effect.