The invention discloses a preparation method of an organic antibacterial film for food packaging. The preparation method comprises the following steps of: S1: drying and dissolving polyether sulfone, polycarbonate, dodecyl trimethyl ammonium chloride and polyvinylpyrrolidone together with an organosilicon cross-linking agent in a dimethyl acetamide solution, performing temperature programming and heat preservation in an autoclave, and performing filtration after cooling to the room temperature, S2: adding copper 8-hydroxyquinoline, sodium dodecylbenzene sulfonate and polyethylene glycol under ultrasound, performing filtration and centrifugal defoamation to form film casting liquid, and S3: performing uniform slobbering, drying, orientated tension, purging and cooling on the film casting liquid to form the finished product. The method is simple in preparation process; raw materials are cheap and easy to obtain; required equipment is simple; the technical requirement is low; the production cost is low; the prepared organic film is thin, ordered in intramolecular arrangement, high in tensile strength and good in antibacterial effect; and particularly, an antibacterial rate for escherichia coli and staphylococcus aureus can reach above 95%.