Abstract: Polyacrylonitrile(PAN)-based carbon fibers (CFs) were coated with a carbon film by chemical vapor deposition using acetylene as precursor. The morphologies of the as-received and modified CFs were observed using SEM and AFM, and their mechanical properties, crystalline parameters, and electrical conductivity were measured after graphitization. It was found that the graphitized CFs that were prepared showed excellent mechanical properties (2GPa for strength and 270GPa for modulus) and good electrical conductivity, (5×10−4Ω cm) compared with the unmodified ones.