Polyacrylonitrile-methylmethacrylate-carbon nanotubes (AMMA-CNTs) copolymer nanocomposites with different contents have been prepared by means of in situ polymerization process successfully. The AMMA-CNTs copolymer nanocomposites are desirable for many important applications. We measured the microhardness of the AMMA-CNTs copolymer nanocomposites. It was found that CNT could increase the microhardness of the nanocomposites effectively. A friction and wear tester under dry conditions investigated the tribological behaviors of the nanocomposites. Compared with pure AMMA, AMMA-CNTs copolymer nanocomposites showed not only smaller friction coefficient but also higher wear resistance. CNT could reduce the friction and improve the wear resistance behaviors of the nanocompsites dramatically. The mechanisms of the significant improvements on the tribological properties of the AMMA-CNTs copolymer nanocomposites were also discussed.