The edible starch composite films were prepared by modification with chitosan, and the structure and properties were studied. The composite films were obtained by casting method for the homogeneous mixtures of the chitosan acetic acid solution and the starch paste. The effects of the chitosan, glycol and NaCl contents on the mechanical properties and water vapor transmission of the composite films were analyzed. And also the structures and properties of the composite films were characterized by X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. The two components for the composite films, starch and chitosan, had excellent compatibility. The addition of glycol and NaCl was beneficial for the plasticization of starch, and also the flexibility of the composite films was improved although they influenced the mechanical strength and WVTR. When the weight ratio of starch and chitosan was 5∶3, and the contents of glycol and NaCl were 25% and 5% , respectively, the obtained edible composite films had the perfect comprehensive properties.