With 2D70 aluminum alloy as the research object, this article studied anodizing process with boric acid and sulfuric acid for electrolyte; The Boric-sulfuric acid anodic oxide film of preparation, meeting the quality of oxide film, took resistantance to salt spray for 336h, and then whether the specimen surface rust was observed; With Five factors, voltage, temperature, boric acid concentration, sulfuric acid concentration, and time, the process parameters to meet the boric-sulfuric acid anodized aluminum alloy was determined. The anodic oxide film of preparation and the conventional anodic oxide film were subjected to film rupture and circulation comparative tests, which proved the fatigue resistance of anodic oxide film prepared with boric acid and sulfuric acid is better than the one of conventional sulfuric acid anodizing film.