Abstract: The corrosive behavior of rare earth Ce on 2A12 aluminum alloy in a simulated atmosphere marine atmosphere containing Cl^-was studied by alternate immersion accelerating test. The as cast micro-topography was observed by metallographic microscope, and the elemental composition of the corrosion products was analyzed by energy dispersive spectroscopy (EDS) . The law of corrosion kinetics of 2A12 aluminum alloy was analyzed by weight loss method, and the electrochemical behavior of 2A12 aluminum alloy after corrosion was analyzed by electrochemical polarization curves. The results show that the addition of rare earth makes the uniformity of 2A12 aluminum alloy improve. The corrosion rate decreases obviously, the corrosion current density decreases, and the corrosion voltage increases.The addition of rare earth Ce makes 2A12 aluminum alloy rust layer more dense, which can cause the electrochemical reaction on the aluminum alloy substrate surface to be slow.