The invention discloses a nano-fiber anti-microbial fruit-vegetable preservative film with a porous structure, and a preparation method and application. According to the invention, myoporum bontioides leaves are grinded into powder and treated by supercritical extraction, so that a myoporum bontioides extract is obtained; a water solution containing TWEEN-80 is added into the myoporum bontioides extract, and the mixture is filtered, so that a myoporum bontioides supercritical extract solution is obtained; the myoporum bontioides supercritical extract solution, a polyvinyl alcohol solution, a chitosan derivative solution and a nano-titania solution are mixed, so that a mixed spinning solution is obtained; and the mixed spinning solution is treated by spinning of a static spinning machine, so that the nano-fiber anti-microbial fruit-vegetable preservative film with the porous structure is obtained. The preservative film has the advantages of a large specific area, a high porosity, high finger uniformity, good mechanical properties and the like, also has performance such as a good moisture permeable and gas permeable property and a good moldproof and anti-microbial property, and has high application potential in the food packaging field.