Oxide membranes are one kind of porous materials with many nano-sized pores. In our work, the two-step anodization method was used to fabricate Anodic aluminum oxide (AAO) membranes. The surface, cross-section micrographs and chemical composition were analyzed by field emission scanning electron microscopy (FESEM). From the FESEM micrographs, it can be easily seen that the self-ordered hexagonal pore channels were parallel and perpendicular to the surface of membrane when AAO membrane was prepared in oxalic acid at 0.2mol/L for 4h. In addition, the biggest pore diameter was 78nm, and the thickness ranged from a few microns to tens of microns in the suitable preparation parameters.