Abstract: Carbon nanotubes (CNTs) reinforced AZ91 magnesium alloy composites were fabricated by powder metallurgy method and followed hot extrusion process. The friction and wear properties, wear morphology and wear mechanism of the composites under dry sliding friction conditions were investigated and compared with that of AZ91 magnesium alloy matrix . The results show that the friction and wear properties of the composites were better than that of AZ91 magnesium alloy matrix due to the effect of self-lubricating and strengthening of CNTs. Moreover, the friction factor of the composites gradually declined with the increase the load and the content of CNTs. In addition, wear mass loss of the compositse increased with the increase of the load. However, under the same condition of the load, the wear mass loss of the composites decreased with increase the contents of CNTs. The main wear mechanism of AZ91 magnesium alloy were fatigue wear and abrasive wear, and that of the composites was slight adhesive wear and abrasive wear.