Abstract: This article briefly describes the method and applications of isotopic dilution massspectrometry (IDMS). The Certified Reference Ma terials with natural isotopic abundancewere used as primary materials to certify the conccntration of enriched isotope byIDMS. Then certified enriched isotopes were used as a spike to certify unknown elementscontent in the standard reference materials by IDMS. With the methods described in thepaper, we have respectively finished determination of Li, K, Mg, Fe,Cu, Ni, Cd, Mo, Pb,etc. The determined matrixes included acid rain, mussel, urine, deep-sea sediment. Wehave got very good achievements in three international compare with IDMS.