The dry friction and wear tests of cemented carbide and Al–50% Si alloy were carried out to explore effects of load and sliding speed on the friction and wear properties of Al–50% Si alloy and wear mechanism of the cemented carbide. The results show that friction coefficient changes in three stages with time: running-in stage, transition stage and stable stage. The wear amount of Al–50% Si alloy increases with the increase of load and sliding speed. The wear mechanism of Al–50% Si alloy at low sliding load is delamination wear; when the load exceeds 50 N, the wear mechanism of Al–50% Si alloy changes to “abrasive wear+delamination wear”. At low sliding speed, the wear mechanism of Al–50% Si alloy is “delamination wear + abrasive wear”; with the increase of sliding speed, the wear mechanism is mainly delamination wear. Moreover, the surface of cemented carbide ball has wear features of scratch, adhesion, and delamination, and wear mechanism of adhesive wear and abrasive wear.