Abstract: The method of determination of Zr,Nb,Ta and Ru in uranium oxide by ICP/MS with chromatography has been developed in this work.The uranium oxide sample was dissolved with HNO 3 and a little HF.The matrix uranium was separated by a chromatographic proess when the CL-TBP was used as a fixed phase and the mixture of HNO 3 and oxalic acid as eluent.The Zr,Nb,Ta and Ru were determined by ICP/MS.The detection limits of Zr,Nb,TA and Ru are less than 10 -8 g/g.Recoveries of the method are between 93%-103% and precisions of the method for 8 samplings are less than 17%.The method developed in this work is useful for the quantitative analysis of Zr,Nb,Ta and Ru in the reference substance of U 3O 8,and the results for those elements are in agreement with the certified values.