An oxide film was prepared on the surface of 7475 aluminum alloy by AO (anodic oxidation), and the corrosion behavior of the obtained AO film in 5 ± 0.5% NaCl solution was investigated. The surface–interface morphologies, chemical compositions and phases were analyzed by means of field emission scanning electron microscopy, energy dispersive X-ray spectrometry and X-ray diffraction, respectively, and the chemical elements of the surface and bonding interface were analyzed by a plane scan and line scan after salt spray corrosion. The results show severe corrosion on the original sample surface, the corrosion products are mainly composed of Al oxide after salt spray corrosion. The AO film is only slightly corroded, and the AO film–substrate is still metallurgically combined. Pitting corrosion in the aluminum alloy, primarily caused by Cl − , is the main mode of salt spray corrosion. There are stratified enrichments of Al and O in the AO film interface after the salt spray test, which are related to pitting corrosion and spalling phenomena, while the other elements were uniformly dispersed. The continuous Al 2 O 3 in the AO film effectively prevents Cl − from eroding the metal substrate to improve salt spray corrosion resistance of the 7475 aluminum alloy.