Abstract: Carbon nanotubes were synthesized using chemical vapor deposition. The influences of reaction conditions and the addition of La to a Ni-based catalyst on the formation of carbon nanotubes were investigated. The morphologies and graphitization degree of nanotubes were determined by TEM, XRD. It was found that the optimum temperature and time were 600℃ and 60min respectively. The addition of La to the Ni-based catalyst produced smaller diameter carbon-nanotubes. The carbon nanotubes possess a well-graphitized structure and high thermal stability.