A simple galvanic reduction for direct growth of An nanowires on silicon wafers is developed. The nanowires were prepared by reacting HAuCl4(aq) with Sn-(s) in the presence of CTAC((aq)) (cetyltrimethylammonium chloride) and NaNO3(aq), which were important to the product morphology development. The nanowire diameter was 50-100 nm, and the length was more than 20 mu m.