Abstract: The SiC nanoparticle reinforced pure aluminum metal matrix composites (Al MMCs) were prepared through a powder metallurgy technique. Their microstructures and tensile properties were investigated. The results showed that SiC nanoparticles enhance the strength of pure aluminum significantly even if their content is very low, with the nanoparticles uniformly dispersed in the Al matrix. However, when the content becomes higher, the SiC nanoparticles are easily agglomerated to lower their strength enhancement effect on aluminum. The tensile fracture showed that the damage mechanism of the Al MMCs changes with the changing content of SiC nanoparticles.