A research has been conducted on the effects of different anodizing times on the exfoliation corrosion resistance of 2A12 aluminum alloy by means of scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS) and film thickness measurement. The results show that with the increase of anodizing time, the thickness of anodic oxide film increases gradually, with an improved performance in the anti-exfoliation corrosion. With the anodization time extended from 30 min to 60 min, the thickness of the oxide film increases from 2.43 μm to 4.72 μm, meanwhile, the standard deviation of the film thickness decreases from 0.75 to 0.52. However, when the anodizing time exceeds 60 min, the thickness of the oxide film increases slowly, with the standard deviation of the film thickness gradually tending to be a level value. A comprehensive analysis of macroscopic and microscopic morphology shows that the corrosion resistance of the alloy is characterized with the best performance with an anodizing time of 60 min.