Abstract: To research bio-based composite edible films for food preservation,hyaluronic acid/gelatin composite films which combined hyaluronic acid solutions with different molecular weight of gelatin was prepared by casting method. The effect of molecular weight of hyaluronic acid on thickness,density,tensile strength,opacity,color,solubility,water vapor transmission rate and moisture content of the composite film were studied,and the compatibility of the composite film was characterized by infrared spectroscopy. The results showed that,with molecular weight of hyaluronic acid increasing,the thickness,moisture content and opacity of the composite film increased first and gradual decreased followed,and the solubility and water vapor transmission rate decreased. The characteristic peak of the amide A region migrated to short-wave in the infrared spectrum,which showed hydrogen bond between the hyaluronic acid molecule and the gelatin molecule. The composite film had high performance with molecular weight of hyaluronic acid from(0.8~1.0)×10⁴ Da. The hyaluronic acid-gelatin composite film has potential applications in edible coating material for perishable food preservation