Abstract: This paper is concerned with the determination of microamount plutonium inexcrement and tissue samples. After the organisms are detroyed completely withHNO_3-H_2O_2-HClO_4, the PuO_2 can be dissolved with 0.48 mol/l HF-15 mol/l HNO_3.The Pu can be converted into Pu (IV) with Fe(SO_3NH_2)_2 and NaNO_2. Thenchromatographic extraction column TOA-xylene-Kel-F is used to separate andpurify Pu (IV). The column is washed with 4 mol/l HNO_3, 10 mol/l HCl toremove U, Th. Am and other interfering nuclides. Finally, the Pu is stripped with0.025 mol/l H_2C_2O_4-0.15 mol/l HNO_3-0.3 mol/l NH_4NO_3and directly electrode-posited onto a plate. The sample plate is measured by a low-background α coun-ting instrument. The method is simple and rapid. The recovery of Pu is 85--90%. Thedetection limit is 3.9×10~(-4)Bq, and the precision better than±15%.