Abstract: In this method for the analysis of Pu(Ⅲ) and Pu(Ⅳ) in nitric acid D_2-EHPA is used as extractant and urea is used as inhibitor of nitrous acid. Thestanding time of the mixture of urea and nitric acid used as analytical mediumhas considerable influence on the extraction behaviour of Pu(Ⅳ), and thestabilization of Pu(Ⅲ) in the analytical process. Under appropriate conditions,the accurate determination of Pu(Ⅲ) and Pu(Ⅳ) can be accomplished.