The invention relates to a composite material of silicon carbide and carbon nanotube and a preparation method thereof. Macroscopic bodies of the carbon nanotubes are used as performs, a chemical vapor deposition method is used for pyrolysis of a silicon-containing precursor, and then the silicon carbide is deposited on the carbon nanotube to prepared the composite material of the silicon carbide and the carbon nanotube, with a mass percent of the carbon nanotube being 0.5-90 %. By selecting the macroscopic bodies of the carbon nanotubes of various orientations and arrangements as performs, the composite material of the silicon carbide and the carbon nanotube with high dispersion, high volume content and various orientations and arrangements can be obtained. By designing fiber performs, the composite material of the silicon carbide and the carbon nanotube with various forms such as fibers and blocks and various sizes can be constructed and prepared. The composite material of the silicon carbide and the carbon nanotube with various mechanical and electrical properties can be obtained, and may be used as high-performance composite materials, conductive and thermal conductivity materials and functional materials in fields of aerospace, national defense equipment, functional material devices, etc.