The alloy catalyst has been widely used because it will be able to improve the activity and selectivity of the single metal catalyst in a given chemical reaction. In this study, the preparation and characteristics of nanosized Pt and Au particles on alumina and their catalytic activity were described. Nanosized Pt-Au catalysts were prepared by impregnation (IMP) method and deposition (DP) method using alumina or ZnO/Al2O3 as support. The size of Pt and Au particles were observed by transmission electron microscopy (TEM), and energy dispersive spectroscope (EDS). TEM images showed that Au particles were well dispersed in the Au[DP]/Pt[IMP]/Zno/Al2O3 catalyst of which Au particles was supported by deposition method.