Carbon nanotube was used to carburize the surface of medium carbon steel and mild steel, respectively, by means of laser surface remelting. The slurry of carbon nanotube of ethanol was coated on the surface of the materials prior to laser irradiation. Microstructures, microhardness and wear property of the surface layers treated by different laser performance parameters were studied. Graphite coating was also used for carburizing. The results showed that both carbon nanotube and graphite were dissolved in the surface molten layer, leading a carburized hardening layer on the surface of the substrate. However, different microstructures formed in the carburizing layers, depending mainly on the type of carburization materials, carbon nanotube or graphite. The carbon nanotube hardening layer exhibits a little higher hardness than the graphite hardening layer. The carburized layer greatly increases the wear resistance of the base material. (C) 2008 Elsevier B. V. All rights reserved.