The invention relates to a platinum sample plate cleaning method, in particular to a platinum sample plate cleaning method using a selective hydrogenation catalyst. Residues obtained after decomposition of ethylene tar at 700 DEG C are aromatic compound components difficult to crack at 700 DEG C. By means of the catalyst, tar can be cracked at low temperature at the oxygen atmosphere, a carrier is a heat-resistant inorganic oxide, palladium serves as an active component, and active components can also contain other elements besides the noble metal of palladium. By means of the method, a platinum sample plate contaminated by ethylene tar residues can be cleaned, and the platinum sample plate is protected.