The anodic aluminum oxide (AAO) templates on polycrystalline silicon substrate are studied for growth of ordered nano-dot arrays in order to fabricate the porous silicon layers. The AAO templates on polycrystalline silicon substrate with pores of average diameter 50nm were successfully prepared by one-step anodization of high pure aluminum layer deposited on polycrystalline silicon in oxalic acid solution. Scanning electron microscopy (SEM) showed that alumina nano-pore arrays were nicely constructed with smooth wall morphologies and well-defined diameters.