Abstract: This paper describes the quantitative determination of rare-earth elements cerium, dysprosium and non-rare-earth elements copper, lead and homogeneity examination of these elements in yttrium oxide reference material by isotope dilution-spark source mass spectrometry (ID-SSMS). The sensitivity of this method is ～10~(-5)—10~(-7)％. The precision is better than 6％. The accuracy is better than 5％. The interferences to the spectra and the best added amount of the isotope tracers are discussed. The choice of the conductive materials for the sample electrodes is also studied.