Abstract: In order to study new biodegradable antimicrobial packaging materials, the antimicrobial films were prepared by incorporated different volume fraction cinnamon oil into alginate solution, and then the physical properties of film thickness, transparency (T), color, water vapor permeability (WVP) and antimicrobial properties were studied. The film thickness had nearly not changed when the volume fraction of cinnamon oil in the film forming solution increased from 0 to 1.0%, but increased significantly when the volume fraction of cinnamon oil reached to 1.2%. The film transparency decreased significantly but WVP increased with the increase of cinnamon oil. Cinnamon oil had an obviously effect on the film color, with the significant increase of a and b values. The film displayed obvious antimicrobial efficiency, when the volume fraction of cinnamon oil in the film forming solution arrived at 0.8%. In conclusion, the film made by alginate film forming solution with the volume fraction of cinnamon oil of 0.8% was of better antimicrobial efficiency and better physical properties. The study can provide a reference for the processing of biodegradable antimicrobial cinnamon oil/alginate film.