In this study arc erosion properties of Cu-30vol%gaphite, Cu-30vol%WS₂ and Cu-30vol%MoS₂ composites were investigated. The results demonstrated that graphite cannot beSmelted and mainly lost in the form of oxidation during the arc discharge process because of its extremely high melting point. In contrast, WS₂ and MoS₂ were melted and even reacted with Cu matrix due to the high temperature caused by arc discharge. Therefore, the arc erosion resistance of Cu-30vol%gaphite composite was better than those of Cu-30vol%WS₂ and Cu-30vol%MoS₂ composites. The main arc erosion mechanisms of Cu-based self-lubricating composites were found to be oxidation, melting, ejecting, internal chemical reaction and fatigue peeling.