Abstract: Anodic aluminum oxide（AAO） is a typical self-organized porous membrane material fabricated in an acidic electrolyte by applying voltage to anodize the metal aluminum. AAO have a wide usage in modern nano-material technology such as nano-array preparation, nano-copy, quantum dots, etc. The pore diameter and roundness are two crucial parameters of evaluating AAO. In this paper, AAO templates are fabricated by two-step method, and the dependence of nano-pores with acid and voltages have been investigated. Results show that the anodization voltage and the concentration and the heat distribution of the electrolyte have significant effects on the quality of the sample.