Abstract: Alternating test of corrosion and fatigue for 2A12-T4 aluminum alloy was designed to explore the damage behavior in the interactive effect of corrosion and fatigue. The results show that the effect of corrosion and fatigue coupling decreased the fatigue life significantly. Small cracks initiated on the specimen surface from the corrosion pits in the direction perpendicular to the loading direction. Under the alternation of corrosion and fatigue, there were multiple fatigue crack initiation sites on the fatigue fracture surface. The present condition of alternating corrosion and fatigue experiment was much closer to the real environment for aircraft using.