The invention discloses antibacterial finishing liquor and application thereof. The antibacterial finishing liquor comprises a silver sulfide nano-material disperse system and a cross-linking agent, which are separately preserved. When in use, the silver sulfide nano-material disperse system and the cross-linking agent are compounded to enter a solvent dispersion liquid. The silver sulfide nano-material disperse system is prepared by the following method: (1) mixing higher fatty acids and water-soluble alkylamine at 25-70 DEG C, adding water and continuously mixing; (2) dropwise adding a water-soluble silver salt solution, mixing until the system turns transparent, continuously mixing, and adjusting pH to 9-12; and (3) dropwise adding a water-soluble sulfur salt solution, mixing and reacting, cooling and filtering, and collecting a filtrate. The antibacterial finishing liquor is very stable, has good dispersity, and has a good broad-spectrum antibacterial effect. After 50 times of standard soaping, cotton textiles treated by the use of the antibacterial finishing liquor still have a very high antibacterial rate to a plurality of bacteria.