The invention relates to an antibacterial composite material, which is prepared from the following components by weight: 120-140 parts of an ABS resin, 4-10 parts of a silver-loaded antibacterial agent, 1-5 parts of a silane coupling agent, 1-3 parts of a reactant, and 4-10 parts of other auxiliary agents such as diffusion oil, a compatibilizer, an antioxidant, and the like, wherein pre-treating is performed with an antibacterial agent to prepare an antibacterial masterbatch, and the antibacterial masterbatch is subjected to lamination to obtain the product. The preparation method comprises: dissolving KH550 in an organic solvent, decomposing under the action of HAC, combining with a silver-loaded antibacterial agent carrier to obtain a pretreated antibacterial agent, uniformly mixing the antibacterial agent, ABS, a compatibilizer, an antioxidant, diffusion oil and other auxiliary agents, adding the mixture to a twin-screw extruder, carrying out melt extrusion to obtain an extruded material, cooling the extruded material, granulating to obtain an antibacterial masterbatch, and laminating to obtain the antibacterial composite material. According to the present invention, the antibacterial plastic has characteristics of strong antibacterial property, long antibacterial effective period, easy processing, high antibacterial property, excellent mechanical property and the like, and has obvious antibacterial effects on Staphylococcus aureus and Escherichia coli.