The invention discloses a preparation method of an anodized aluminum film of a through hole. The preparation method mainly comprises the following steps: after a high-purity aluminum sheet is subjected to annealing, oxide layer removing, degreasing and electrochemical polishing treatment, placing into an anodizing electrolytic cell to carry out primary anode oxidation by taking oxalic acid, sulfuric acid or phosphoric acid solution as electrolyte, after an oxide layer is removed through treatment of mixed aqueous solution of chromic acid and phosphoric acid once, the secondary oxidation is carried out under the same conditions, the residual aluminum-based substrate is removed in acid solution, and reaming is carried in the phosphoric acid, so that the anodized aluminum film of the through hole with small aperture, and the controlled aperture and thickness is obtained. According to the invention, the relatively cheap device is used, through the simpler process, a large amount of anodized aluminum films of through holes can be simply and uniformly prepared in a lossless manner, and heavy metals are not introduced in a process of removing the residual aluminum substrate, so that environmental pollution is reduced. The prepared anodized aluminum film has the advantages of good uniformity and repeatability, highly ordered nanometer pore passage, uniform period, and controlled thickness and aperture.