The Ni(OH)2/SiO2 binary colloid was prepared using Ni(NO3)2.6H2O and (C2H5 O)4SiO4 as starting materials and was used to form NiO/SiO2 composite powder by hydrothermal method and desiccant method in open air respectively. Multiwalled carbon nanotubes (MWCNTs) were synthesized respectively by chemical vapor deposition using the NiO/SiO2 catalyst prepared by different methods. The phase and morphology of the catalysts and the morphology, output yield and purity of MWCNTs were compared by XRD, TEM and SEM. The results show that the catalyst powder prepared by hydrothermal method, compared with that by desiccant method, is smaller, better dispersion and has stronger catalytic activity. Pure MWCNTs with smaller tube diameter and narrow range could be obtained at a high yield using that NiO/SiO.2 powder prepared by hydrothermal method as catalyst.