Abstract: The ratios of 190Os/184Os and 96Ru/102Ru for the residues of the Nadan and the Yongning iron meteorites, as well as for the metal phases of the Jilin and the Taonan stone meteorites,are determined by RNAA. Before that,Nandan and Yongning iron meteorites are pretreated by dissolution in 2 mol/1 H2SO4. All factors affecting Os and Ru isotopic abundances during the processes of irradiation,separation and measurement have been taken into consideration. The statistical errors of measurement for the ratio of 190Os/184Os can be controlled to be less than 1%. The experimental results indicate that the statistically significant anomalies affecting isotopic 190Os/184Os and 96Ru/102Ru abundance have not been found relative to commercial Os and Ru chemicals.