The improved reagent formula and optimized procedure of nickel sulphide fire assay have been developed for the determination of PGEs in black shale samples by Inductively Coupled Plasma-Mass Spectrometry (ICP-MS). The addition of Potassium nitrate as an oxidant of the fusion flux increases the recovery of PGEs by about 10%. After digestion by HCl, there was still a great amount of precipitations on the bottom of the beaker. This problem was resolved by adding a moderate amount of ferric chloride (about 2~3 mL) with a hot solution and stirring. The results of different black shale samples are in good agreement with the reference values, showing that the method is reliable for determining the PGEs in black shale samples.