The influence of Al content on the Mg-Al alloys corrosion performance during sodium chloride induced at- mospheric corrosion has been studied. It was found that the corrosion rate of three Mg-Al alloys was accelerated with increasing Al content. The poor corrosion resistance was attributed to the galvanic coupling between the β phase and eutectic phase or α phase and the formation of porous corrosion products. The influence of Al content on the Mg-Al alloys corrosion performance during sodium chloride induced at- mospheric corrosion has been studied. It was found that the corrosion rate of three Mg-Al alloys was accelerated with increasing Al content. The poor corrosion resistance was attributed to the galvanic coupling between the β phase and eutectic phase or α phase and the formation of porous corrosion products.