The work aims to prepare a green composite film with excellent properties based on chitosan, gelatin and apple polyphenols. A chitosan / gelatin / apple polyphenol blending film was prepared by solution mixing. Its degradability was tested by the soil embedding method. It was characterized by infrared spectroscopy, X-ray diffractor and scanning electron microscopy. And its mechanical properties were also tested. The results showed that the mechanical strength of chitosan / gelatin and apple polyphenol composite films increased first and then decreased with the addition of apple polyphenols, with better tensile strength at 1%; chitosan, gelatin and apple polyphenols had good compatibility; the composite film had good biodegradability. Adding appropriate proportion of apple polyphenols can effectively improve the mechanical properties of the composite film. The prepared biodegradable composite film has a wide application prospect in green food packaging.