The invention relates to a preparation method of multi-wall carbon nanotubes, in particular to a method for directly preparing multi-wall carbon nanotubes with high specific surface area by using a chemical vapor deposition method. The method comprises the steps of preparing a catalyst with excellent catalytic performance by adopting a precipitation freeze-drying method, and cracking C1 hydrocarbon to grow carbon nanotubes in a reactor by using the catalyst. The specific surface area of the multi-walled carbon nanotubes directly prepared by the method is as high as 800-900 m<2>/g, the tube diameter distribution is in a range of 3-5 nm, the length distribution is in the range of several to dozens of micrometers, the purity of a crude product can be greater than or equal to 90 wt%, the purity can further be greater than or equal to 98 wt% after simple pickling, and the obtained carbon nanotubes have the advantages of high quality, low cost and easiness in operation and implementation.