Abstract:Chitosan and gelatin were used as composite film skeleton materials，and 0.3 % （volume ratio）glycerol plasticizer was added to prepare edible composite film with remarkable antimicrobial properties.The optimization of chitosan and gelatin ratio of the film skeleton material was carried out using higher tensile strength，better elongation at break and lower water vapor permeability as the main performance indicators.The results showed that when the concentration of chitosan was 1.5 % and gelatin was 1.25 %，the optimum composite film with good mechanical properties （tensile strength 13.24 MPa，elongation at break 112.45 %）and low water vapor permeability（0.403 2 mg·mm·kPa-1·h-1·m-2）was prepared with the mixing volume ratio at 6 ∶4.The composite films were further characterized by infrared spectroscopy，X-ray diffraction and scanning electron microscopy.The results indicated that compared with the control chitosan and gelatin films，the internal molecules of the composite films had stronger hydrogen bonds and intermolecular forces，and the internal films were dense，so that the water vapor was not easy to pass through.The composite film solution also presented significant inhibitory effects on E.coli，Staphylococcus aureus and Bacillus subtilis.