The invention discloses an organic-inorganic hybrid antibacterial nanomaterial, and a preparation method and a use thereof. The antibacterial material is a core-shell structure, wherein the core is aninorganic antibacterial material, and the shell is an organic antibacterial material; the inorganic antibacterial material is one or more of Ag2O, TiO2, ZnO, CaO, MgO, CuO and Cu2O; the organic antibacterial material is a polymerization product of a polyphenol compound and a polyamine compound, and the polyphenol compound is one or more of dopamine, tannic acid, gallocatechin, catechin and catechol; and the polyamine compound is one or more of polyethylene polyamine compound. The organic-inorganic hybrid antibacterial nanomaterial has the advantages of excellent synergistic antibacterial property, good dispersibility, good interfacial properties, and facilitation of uniform dispersion of the material in a polymer material. The preparation method of the invention has the advantages of simplicity, greenness, environmental protection, and low price and low toxicity of cuprous oxide nanoparticles.