Abstract: Colorchanging film was prepared using PVA as a master liquor,and citric acid as a crosslinking agent,the mechanical and optical properties and thermal stability were studied.With increasing citric acid,the tensile strength of the film increased but elongation at break decreased,the mist degree increased.Citric acid content also had a greater impact on the color of film and color change.The addition of citric acid increased the thermal decomposition temperature of the film.