Abstract: An ion chromatographic method for determination of plutonium in spent nuclear fuel is established. In this method uranium and plutonium-containing sample solution is loaded on an anionic exchange resin column and then eluted with 7.2 mol/L HNO₃ for uranium and 0.1 mol/L HNO₃-0.1 mol/L NaF for plutonium. The eluents are mixed on-line with the postcolumn reagent arsines Ⅲ, and the absorbencies are continuously recorded. The plutonium content is calculated from the plutonium-to-uranium peak area ratio. All these operations are implemented and controlled by a chromatographic workstation. By using this method the interference from uranium and other matrix components is eliminated, the plutoniumto uranium peak area ratio is quite stable and thus no plutonium reference is needed. The method gives an uncertainty of 2.5% and a detection limit of 0.05 mg/L of plutonium. The successful analysis of two real samples shows the feasibility of this method for determination of plutonium in spent nuclear fuel.