Objective: This study aimed to develop polysaccharide-based composite antibacterial films with excellent antibacterial and physicochemical properties to effectively improve the shelf life of food. Methods: Carrageenan, agar, konjac gum and pectin were used as film-forming substrates and natamycin and nano-MgO were used as antibacterialagents to investigate the effects of adding antimicrobial agents on the physical, mechanical and antibacterial properties of the films and the preservation of grapes. Results: After the addition of antibacterial agents, the film thickness, tensile strength and haze increased, air permeability increased and elongation at break decreased, water solubility, swelling and moisture permeability decreased, light transmission and gloss decreased and the color tended to yellow-green, good compatibility with the film filler. It can effectively inhibit the growth and reproduction of Trichoderma, Rhizopus, Aspergillus, Staphylococcus aureus, Escherichia coli, Shigella and Salmonella, among which carrageenan/natamycin/nano-MgO composite membrane （CNM） and agar/natamycin/nano-MgO composite membrane （ANM） with good indicators can delay the water loss rate of grapes, improve the decline in hardness and the reduction of soluble solids content, and ensure the appearance and nutritional quality of grapes. Conclusion: ANM and CNM films are suitable for use as antibacterial packaging materials to extend the shelf life of food products, and are expected to be developed into fruit and vegetable preservation films with antibacterial preservation functions.