The antimicrobial nisin peptide was grafted to the 2,3-dialdehyde cellulose through Schiff's base reaction. The obtained peptidopolysaccharide films had the denser microstructure, lower water holding capacity, and increased mechanical properties than the pristine cellulose film. The peptidopolysaccharide films exhibited promising antibacterial activity toward Gram-positive and Gram-negative bacteria, and the ability to induce bacteriostasis of the N-3 peptidopolysaccharide film was four orders of magnitude higher than that of pure cellulose film. In an extended application, the peptidopolysaccharide antibacterial films were used as packaging materials for fresh pork, the results indicated that the peptidopolysaccharide films readily killed the adhered bacteria upon contact, and the N-3 peptidopolysaccharide film extended the shelf-life of the fresh pork at least for six days as compared with polyethylene wrap. Therefore, these peptidopolysaccharides films represent good potential as a green food packaging material.