The paper studied the fretting properties and the fretting mechanism of AZ91D and AM60B magnesium alloy. The results showed that the AZ91D alloy displayed lower friction coefficient and smaller wear volume than those of AM60B alloy, and also showed superior ability than those of AM60B in resisting crack nucleation and propagation. The fretting wear mechanisms of AZ91D and AM60B alloy were similar, including adhesion wear, surface fatigue wears and abrasive wear.