The invention relates to a three-dimensional network silicon carbide enhanced metal-based composite material and a preparation method thereof. The composite material comprises a metal matrix and a three-dimensional network silicon carbide ceramic enhanced phase. The three-dimensional network silicon carbide ceramic enhanced phase is obtained by siliconizing the surface of the three-dimensional carbon. The preparation method comprises the following steps: foaming and carbonizing a mixture of wood flour and short carbon fibers to prepare three-dimensional network carbon; and siliconizing the surface of the three-dimensional network carbon at a high temperature to prepare the three-dimensional network silicon carbide ceramic enhanced phase and carrying out cast-infiltration to the metal matrix to obtain the three-dimensional network silicon carbide enhanced metal-based composite material. In the composite material prepared by the method, the three-dimensional network silicon carbide ceramic is great in porosity and small in pore diameter, and the three-dimensional network silicon carbide is continuous in a three-dimensional space and forms metallurgical bonding with the metal matrix.Compared with a conventional silicon carbide particle enhanced metal matrix, the composite material has a better integral structure, and not only can play high hardness, high wear resistance and highheat resistance of the silicon carbide ceramic in the three-dimensional direction, but also can keep good toughness and heat and electricity conducting performance of the metal matrix. The prepared composite material shows excellent shock-resistant, impact-resistant and wear-resistant performance in various severe working conditions.