The dry sliding friction wear test of T6 treated Al-20Si-5Cu alloy was performed with UMT-2 tribometer. The wear mechanisms of the alloy were analyzed by means of SEM, EDS and OLS4000. The results reveal that the wear rate of Al-20Si-5Cu alloy is increased with the increase of applied load, but under high applied load, the wear rate is still small, showing a good wear resistance of the materials. The average friction coefficient changes within the range from 0.38 to 0.42, and the change is small over time, which indicates a strong stability. Meanwhile, as the applied load increases, the wear mechanism is changed from the oxidative wear and abrasive wear of low applied load to the fatigue wear.