Abstract: Carbon nanotubes reinforced aluminum matrix composites were fabricated by powder metallurgy method. The influence of different carbon nanobube content on hardness, the friction and wear behavior under steady-state conditions of the composites were investigated. The worn surfaces of composites were observed by scanning electron microscope, and worn mechanism of composites was discussed. The results indicated that the Vikers hardness of composites increased first and then decreased with carbon nanotube content increasing. 2.0% addition by mass of carbon nanotubes to the aluminum matrix of caused increases in the Vikers hardness of about 80%. The friction coefficient of composites was low and decreased with increasing carbon nanotube content. On the other hand, wear rate of composites decreased firstly and then increased. For composite of 1.0% CNTs, the wear mechanism was characterized as abrasive wear and adhesive wear, while the delamination wear and surface fatigue were the mainly mechanism for composite of 2.0% CNTs.