The invention discloses a method for preparing a porous transition metal oxide/carbon composite material. The prepared porous transition metal oxide/carbon composite material is a tremelliform-like structure where nano transition metal oxide particles are embedded in a porous three-dimensional carbon skeleton. The method comprises the following steps: S1, dissolving the hydrated transition metal chloride and the diacid in an alcohol solvent; enabling the solution to react in a high-temperature reaction kettle at 80 to 120 degrees centigrade for 8 to 24 hours; after an orange precipitate is formed, centrifuging the solution to obtaining the precipitate; washing the precipitate with the alcohol solvent, vacuum drying the precipitate at 60 to 80 degrees centigrade for 6 to 12 hours to obtaina metal organic skeleton centered on the transition metal; and S2, heating the metal organic skeleton centered on the transition metal, as a precursor, to 500 to 900 degrees centigrade under the protection of an inert gas, keeping the temperature of a product for 1 to 5 hours, and slowly cooling the product to room temperature so as to obtain the porous transition metal oxide/carbon composite material.