A homogeneous and dense pyrolytic carbon coating was deposited on carbon nanotubes (CNTs),by electrical heating,using ethanol vapor as the carbon source in an argon flow as carrier gas at atmospheric pressure.Microstructure and morphology of the coating and the interface between the coating and CNTs are examined by scanning electron microscopy (SEM) and high-resolution transmission electron microscopy (HRTEM).SEM observations show a uniform and dense pyrolytic carbon coating was formed on the surface of the CNT bundles and in the inter-bundle spaces.The deposition rate for the formation of the carbon coating is calculated to be 3 μ/h.TEM identifies the pyrolytic carbon deposited over the CNT bundles are well crystallized graphite.