The invention provides a preparation method for intelligent chromogenic antibiosis antioxidant freshness-retaining film. The method comprises the following steps: firstly preparing a mother solution of polyvinyl alcohol, adding nanometer titanium dioxide to prepare a PVA-nano TiO2 mixed solution, stirring fully, curtain coating on a glass plate through the solution, drying to form a film in an oven, measuring the mechanical properties and antibacterial properties of the film, screening out an optimum adding ratio of nano TiO2, preparing a purple sweet potato anthocyanin solution separately, added the purple sweet potato anthocyanin solution to a solution with an optimum mixing ratio, after stirring fully, curtain coating on the glass plate through the solution, and drying to form the film in the oven. Compared with other saccharides and protein-like films, the film has good mechanical properties, the combination of antibacterial properties and antioxidant properties can better extend the shelf life of food, the films can exhibit different color changes in different pH environments, and the film combines chromogenic, antibacterial, and antioxidant properties and has a wide range of uses in food packaging.