The properties of skin gelatin films of walleye pollock (Theragra chalcogramma) were examined before chitosan was added to improve the properties of the fish gelatin films. The interaction and compatibility of various composition in the composite film were also researched, which would provide theoretic basis and scientific gist for the development of edible films in food industry. Skin gelatin of walleye pollock had good filmogenic property, while the property of composite film was improved greatly with the addition of chitosan. Fish gelatin was miscible with chitosan and the gelatin/chitosan composite films had excellent optical transmittance (higher than 88%). The mechanical property of fish gelatin film was lower, which was examined by texture analyzer. The addition of 80% chitosan and 60% chitosan increased the tensible strength and elongation at break to 182.48% and 430% of fish gelatin. Differential scanning calorimetry (DSC) analysis showed that the thermal denaturation temperature of gelatin/chitosan composite films was 10℃ higher than that of fish gelatin film. Chitosan modified fish gelatin film by decreasing water solubility and WVP sharply, but made hygroscopicity slightly higher. The results suggested that fish gelatin/chitosan composite films exhibited better mechanical property, thermal stability and water resistance than fish gelatin film. Fourier transform infrared spectroscopy (FTIR), Xray diffraction (X-RD) and Scanning electron microscopy (SEM) analysis revealed that chitosan effectively interacted with fish gelatin to form a new macromolecule, and fish gelatin/chitosan had good filmogenic property.