Abstract: The paper describes the technique of accurately measuring concentration of standard solution of Pb, Cd, Mg and determining impurity elements contained in the standard solution of Pb, Cd, Mg, Fe by ICP/MS. With the preparation of standard sample solutions by chemical metrology and the analytical procedures rigidly controlled, the preclsions are better than 1. 5 %. Furthermore, about 56 impurity elements among the standard solutions of Pb,Cd, Mg and Fe are determined- The method, used in this work, is reliable and accurate.