The work aims to study the preparation technology process of Nano-SiO2 modified cassava starch/ PVA/chitosan film, with chitosan, cassava starch and polyvinyl alcohol (PVA) as basic film-forming materials. With elongation at break, tensile strength, transmittance and water absorption as evaluation index, based on single factor test, the influences of the Nano-SiO2 content, the content of dispersant SDBS and the pH value of casing solution on properties of Nano-SiO2 modified cassava starch/PVA/chitosan films were studied through the design of L9 (34) orthogonal experiment. The best process parameters for the preparation of Nano-SiO2 modified cassava starch/PVA/chitosan film were obtained. The mass fraction of Nano-SiO2 was 2.0%, the mass fraction of SDBS was 2.0%, and the pH value of casting solution was 3.0. The ranking of three factors affecting the modified film performance was dispersant content>Nano-SiO2 content>pH value. The best production process parameters of Nano-SiO2 modified cassava starch/PVA/chitosan films are obtained.