The work aims to investigate the effect of self-made modified hydrotalcite antibacterial composite films on the preservation of Chinese flowering cabbage. 5-formylsalicylic acid intercalated hydrotalcites (FSA-LDHs) were added to linear low-density polyethylene. FSA-LDHs/PE composite antimicrobial films were prepared through the extrusion casting process and were tested for the preservation effect on Chinese flowering cabbage. Chinese flowering cabbage was put under FSA-LDHs/PE composite antimicrobial films group, pure polyethylene (PE) films group, and no-packaging group and stored at (4±1) °C for 11 days. The Chinese flowering cabbage was periodically taken out for the characterization of quality indexes, and the preservation effect was evaluated by comparing the relevant quality indexes. The self-made FSA-LDHs composite antimicrobial films showed improved crystallinity, with oxygen permeability decreasing by 81.2% and water vapor permeability decreasing by 46.9% compared to the pure PE films. The antibacterial ability against Escherichia coli and Staphylococcus aureus increased by 29.6% and 22.7%, respectively. This effectively reduced the transmission rate of oxygen and water vapor, and improved the antibacterial ability of the films. In the preservation experiment, it inhibited the increase of weight loss rate, malondialdehyde accumulation and peroxidase activity, and slowed down the decline of stem hardness, chlorophyll, carotenoids, vitamin C, total phenols and flavonoids. The preservation effect of FSA-LDHs/PE composite antibacterial films was better than that of the pure PE films group and the no-packaging group. Compared with pure PE films, the FSA-LDHs/PE composite antibacterial films has a better preservation effect on Chinese flowering cabbage, extending the shelf life by 3-5 days and can replace pure PE films for fruit and vegetable preservation.