Abstract: According to mineralogical and chemical characteristics of cobalt-rich crust samples from the west Pacific ocean,the reagent formula used in common nickel sulfide fire assay preconcentration for PGE analysis were modified.The background of the procedure for PGEs was improved remarkably by reducing the quantity of the collector of carbonyl nickel powder.Ru,Rh,Pd,Ir and Pt was determined by ICP-MS with~(175)Lu as internal standard.Os was determined by isotope dilution-ICPMS.The method has been verified by determination of PGEs in National Standard Reference samples(GBW 07290 and GBW 07291)with satisfactory results.