This standard specifies a method for the determination of palladium content in geochemical samples using thiourea enrichment-graphite furnace Atomic absirption spectropho-tometry, AAS. It is suitable for geological samples containing platinum group elements such as ultrabasic rocks, and the determination range is 1 ng/g to 0.5 µg/g. The method removes sulfur and organic matter by burning the sample, analyses the sample with sodium peroxide and extracts it with water, and then treats it with sulfuric acid and hydrofluoric acid to remove Miscellaneous impurities. In concentrated sulfuric acid medium, the sulfide precipitation of palladium is formed by thiourea, then dissolved and extracted by nitric acid-sulfuric acid, and finally the palladium content is determined by graphite furnace Atomic absirption spectropho-tometry, AAS.