The invention discloses a modified zein nano drug delivery system wrapped by bacterial outer membrane vesicles as well as a preparation method and application of the modified zein nano drug delivery system. The medicine is dissolved in absolute ethyl alcohol, deionized water is added after ultrasonic dissolution, zein is added, and ultrasonic treatment is carried out; quickly adding a sodium caseinate solution into the obtained mixed solution while stirring, and stirring to obtain a modified zein drug-loaded nanoparticle solution; the preparation method comprises the following steps: uniformly mixing bacterial outer membrane vesicles with a modified zein drug-loaded nanoparticle solution, extruding the mixed solution for 2-8 times by using high-pressure nitrogen as an extrusion pressure source through a 200nm polycarbonate film, centrifuging the obtained product, and collecting the precipitate, thereby obtaining the bacterial outer membrane vesicle wrapped modified zein drug-loaded nanoparticle system. The nano drug-loading system provided by the invention is narrow in particle size distribution range and good in stability, and can load hydrophobic drugs which can be dissolved in ethanol, so that the solubility of the hydrophobic drugs in water is enhanced, and the stability and bioavailability of the drugs are improved.