The invention discloses a thermometal-nitrogen-doped carbon-based bifunctional catalyst synthesized through a one-pot method by using nitrogen-doped bio-based porous carbon as a carrier, and a preparation method and application thereof. The catalyst can be used for catalyzing efficient selective hydrogenation of biomasses such as bio-based sorbitol, xylitol, cellulose, lignocellulose, etc. for thepreparation of low-carbon alcohol such as diol, etc. since cheap and renewable biomasses are used as raw materials for preparation of a porous nitrogen-dope carbon material without adding nitrogenousorganic compounds as the nitrogen-doped element, the catalyst of the invention is green and environmentally-friendly and the cost is low. When being used for selective hydrogenation of biomasses in awater-phase system, the prepared metal supported catalyst has excellent of catalytic activity, stability and selectivity. In addition, the separation of products and the catalyst is simple; yield ofglycol and propylene glycol in the products can reach up to 85% and above; the reaction steps are less, the condition is mild, and the operation is simple; and the catalyst has a broad application prospect.