The invention discloses a mildew-resistant finishing method for wool fabric. The method comprises steps as follows: firstly, water is added to a finishing agent, an aqueous solution is prepared and sprayed onto the surface of the fabric with the high-pressure spraying technology, and finally, the fabric is dried, wherein the finishing agent is prepared from components in parts by weight as follows: 5-6 parts of sodium polystyrenesulfonate, 3-6 parts of sodium citrate, 5-10 parts of vinyl versatate, 3-6 parts of butanol, 5-8 parts of soap powder, 15-20 parts of 2-methyl-4-isothiazolin-3-one, 11-14 parts of garlic juice, 16-22 parts of ethylene glycol, 1-8 parts of glycerin, 4-8 parts of dimethylcydosiloxane, 8-10 parts of vinyl trimethoxy silane and 12 parts of zinc acetate. The mildew-resistant finishing method for the wool fabric is safe and effective, and the wool fabric finished and prepared with the method is good in mildew-resistant performance and high in washability, touches soft and is safe and non-irritating after long-term contact with the skin surface.