The invention discloses nanometer antibacterial mildewproof coating. The invention comprises the following components according to the weight percentage of The invention of water-based coating, 3 to 7 percent of nanometer silver, 3 to 7 percent of nanometer copper or nanometer zinc occupies, and 4 to 11 percent of nanometer zinc oxide or nanometer titanium dioxide. The application of the nanometer antibacterial mildewproof coating is as follows: the nanometer antibacterial mildewproof coating is evenly painted on the medical instruments, the medical furniture and the indoor wall bodies of a hospital, such as hospital beds, bedside cabinets, hospital carts, office tables and chairs of a hospital, so as to ensure the surfaces of the articles to be covered through the coating, when harmful microorganisms in air or at the parts of human hands are contacted with the articles, the harmful microorganisms left on the articles are captured and killed through the metallic ions with positive charge in the nanometer antibacterial mildewproof coating, and therefore the invention prevents the cross spreading of the harmful microorganisms in the hospital.