This work aims to study corrosive wear properties of Al-Mg2Si composite coating in 3.5 wt.% NaCl solution. Electrochemical behavior of the samples was tested, and open circuit potential, friction coefficient and dry friction of the samples in 3.5%NaCl solution were monitored in real time with electrochemical workstation (CHI660 E) and corrosive wear tester. Characteristics of grinding cracks were characterized with scanning electron microscope (SEM) and ultra-depth three-dimen- sional microscope. Self-corrosion potential of magnesium alloy was ?1.4888 V, and corrosion current density was 2.817×10?3 A/cm2. Compared with the substrate magnesium alloy, self-corrosion potential of the Al-Mg2Si composite coating shifted positively by 0.5288 V, and corrosion current density of the composite coating decreased by 3 orders of magnitude. During the process of corrosive wear, open circuit potential (OCP) of the Al-Mg2Si composite coating was ?0.9202 V, 0.5713 V higher than that of the substrate magnesium alloy. During the process of dry friction, stability friction coefficient of the coating was 0.28, 0.07 lower than that of the magnesium alloy. Difference between dry and wet wear rate of the Al-Mg2Si composite coating was 44.72×10?4 mm3/(N?mm), 0.52 times as large as that of AZ31B magnesium alloy, and was far greater than corresponding pure mechanical wear rate. Corrosion is the main cause of abrasion loss during corrosive wear process, and the Al-Mg2Si composite coating exhibits better corrosive wear properties than magnesium alloy.