A series of chitosan-gelatin modified by walnut green husk polyphenols with different ratios of chitosan to gelation were prepared,and the mechanical properties, solubility,water vapor permeability (WVP) and DPPH free radical clearance of the modified composite membranes were investigated. The structure and compatibility of the modified composite membranes were analyzed by X-ray diffraction(XRD),infrared spectroscopy (IR)and Scanning Electron Microscope (SEM).The results show that the comprehensive performance of modified composite membrane is the best when the dosage of polyphenols is 2% and the ratio of chitosan to gelatin is 45:55. The tensile strength, solubility, WVP, DPPH free radicals clearance of the modified composite membrane respectivily are 49.8 MPa, 16.5% ,0.15 (g. m.)/(h.m2. kPa) and 80.40%. The crosslinking of polyphenols with chitosan and gelatin and the compact structure also with the good compatibility of the modified composite membrane are indicated by XRD,IR and SEM. The research illustrates that walnut green husk polyphenols can improve the internal structure and promote the comprehensive performance of the modified composite membrane.