In this study, Al-Si alloy protective coating was deposited on the surface of ZM5 magnesium alloy by cold spray technology. Researchers observed the surface morphology of the coating by SEM, and researched tribological properties of the substrate material and the coating. The results show that, the bonding mechanism of the Al-Si alloy coating and substrate is metallurgical bonding and mechanical interlocking. The abrasion mechanism of Al-Si alloy coating is adhesive wear. The friction coefficient of the coating is higher than magnesium alloy in different friction frequencies. Greater change in friction coefficient is caused by the inhomogeneous phase composition. But the wear track depth of the coating is smaller than magnesium alloy. Wear-resisting property is improved.