The pursuit of sustainable plastic packaging materials stimulates the development of new materials based on renewable resources and efficient fabrication methods. In this study, thermoplastic hydroxypropyl starch (TPS) as a matrix and oxidized microcrystalline cellulose (MCC) as a reinforcing agent were used to prepare watersoluble composite films via a hot-compression molding technique. As-prepared composite films were disintegrated in water in approximately 60 s, which could potentially reduce plastic pollution in the environment. In addition, MCC was treated to enhance the tensile strength of composite films, with a remarkable increase of similar to 249.42%. The composite films are composed of renewable, biodegradable, and environment-friendly materials, and the fabrication process is environmentally benign, highly efficient, cost-effective, and easy for scaling up. The new composite films can be used as a renewable water-soluble material for industrial applications.