Friction and wear behaviors have been studied between the untreated base material and the friction stir welds of 5052 aluminum alloy. To determine the wear mechanism surface microstructures of worn test samples were examined by scanning electron microscopy (SEM).Variation rule of wear-resistance property and coefficient of friction were investigated according to wear mass loss and moment of friction under different parameter condition. The results show that all of friction stir welds had lower coefficients of friction and higher wear resistance than base material. The abrasion loss of base material increased by six times when position pressure increased from 50N to 100N and the abrasion loss is as 10-20 times as that of friction stir welds. The value of friction-moment of friction stir welds is low and stable and abrasion principle had changed from grain abrasion to fatigue wear. Surface examination showed that adhesion and smearing was the main wear mechanism for friction stir welds.