The invention discloses a sol-gel method for preparing nano vanadium carbide powder. Sucrose is taken as a carbon source, and ammonium metavanadate is taken as a vanadium source. The method comprises the following technological steps of: preparing materials, preparing a precursor, drying the precursor, charging the materials, performing high-temperature heat treatment, and sampling. Therefore, the high-purity nano vanadium carbide powder is prepared through different heat treatment processes. The vanadium carbide powder prepared by the method has the mean grain size of 14 to 20nm and the mean granularity of 20 to 40nm. The method has the advantages of simple process, low cost, and easy realization of large-scale preparation.