Addition of biomass-based ESO as a novel plasticizer in EC resulted in better film performances than conventional EC films with or without other commercial plasticizers. The tensile strength, elastic modulus, elongation, folding endurance and burst- ing strength of ESO–EC films were similar to or even better than those of corresponding DBP–EC and TEC–EC films, especially for ESO-15. ESO–EC films showed good thermal stability and non- flammability. Meanwhile, ESO decreased the Tg from 124◦C (pure EC film) to 71◦C (ESO-25), which could facilitate the processing of films. ESO reduced the oxygen and water vapor permeabilities of EC films as a result of its hydrophobic nature and the compact structure of ESO–EC films. In summary, ESO–EC film, which is com- pletely biomass-derived material, has great potential to substitute conventional plasticized films in various fields.