The invention belongs to the field of material metallurgy, and particularly relates to a carbon-coated vanadium-containing composite and a preparation method thereof. The preparation method includes the steps that a, a liquid conductive agent is prepared, wherein a pre-added conductive agent is dissolved in solvent, stirring is conducted, the solution pH value is regulated, and the liquid conductive agent is obtained; b, a composite precursor is prepared, wherein the liquid conductive agent is added to a vanadium-containing solution, precipitator is added, the solution pH value is regulated, heating and precipitating are conducted, and the carbon-coated vanadium-containing composite precursor is prepared; c, the carbon-coated vanadium-containing composite is prepared, wherein the carbon-coated vanadium-containing composite precursor is baked for 1-2 h at the temperature of 300-400 DEG C and is then baked for 2-4 h at the temperature of 700-800 DEG C to obtain the carbon-coated vanadium-containing composite. The preparation method is simple, the problem that in the prior art, the mechanical grinding time is long is solved, and even mixing under the molecule scale is achieved.