Two-dimensional diffraction grating was fabricated on aluminum plate on the basis of anodization technique. The reflective grating with interpore ranging 500 nm was prepared using mild anodization. In order to make the porous alumina arrays a single step mild anodization in 0.4 M phosphoric acid with 195 anodization voltage was employed. Interpore distances were seen 500 nm when the mild anodization technique was used. The domain size of hexagonal ordered arrays was observed with over 25 µ2 area. Optical properties of gratings were investigated using visible light sources thereby the structural details of gratings were determined.