Abstract: With nickel nitrate as catalyst precursor, the carbon nanotubes (CNTs) were prepared by the method of catalytic pyrolysis of phenolic resin. The effects of pyrolysis temperature and catalyst content on the synthesis of CNTs were investigated by X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results show that at the pyrolysis temperature of 400 ℃, no CNTs were formed in the pyrolytic products of phenolic resin with 0.75wt%Ni. At the pyrolysis temperatures of 600-1 000 ℃, the yield and length-diameter ratio of CNTs first increased then decreased with the increase of temperature and the optimal growth temperature was 800 ℃. When pyrolyzed at 800 ℃, the yield and length-diameter ratio of CNTs first increased then decreased with the increase of nickel content and the optimal nickel content was 0.75wt% of phenolic resin. Under this condition, the diameters of synthesized CNTs were 30-60 nm and the lengths were tens of microns.