The work aims to study the effect of glycerol on the performance of the composite film, by adding different mass fractions of glycerol as the plasticizer, with the chitosan-starch composite film as the research object. The chitosan solution and the maize starch solution were mixed at a volume ratio of 6∶4. With a certain amount of glycerin added, the film was cast into acrylic sheet. The mechanical properties of the film were measured by universal testing machine and its morphology was observed by scanning electron microscopy, and the film was subject to infrared scanning and X-ray dif-fraction analysis. Glycerol had great compatibility with starch and chitosan. When the mass fraction of glycerol was between 35% and 55%, the tensile strength of the film decreased and the elongation at break increased with the increase of glycerin content. The tensile strength was up to 33.57 MPa and the elongation at break was up to 80.39%. Glycerin, as a plasticizer, can improve the mechanical properties of the film and offers the potential for wide application of edible films.