The work aims to explore the influence of 60Co γ-ray irradiation dose on the structure and properties of cellulose nanofibrils (CNFs) film in order to balance the relationship between the irradiation dose of 60Co γ-ray sterilization of cellulose nanofibrils (CNFs) film and the properties of the film, thus obtaining an appropriate dose of irradiation having minor effects on the properties of CNFs film. CNFs were produced by mechanical grinding method with bagasse pulp board as the raw materials and then CNFs films were prepared through pouring process. The CNFs films were irradiated with gamma irradiation at doses of 5~50 kGy, and then the surface morphology, chemical structure, crystallinity, thermal stability, mechanical properties, and barrier performance of the films were tested. With the increase of irradiation dose, the fibrous structure of CNFs became uneven in thickness, indicating that CNFs had undergone oxidative degradation caused by irradiation. In addition, the tensile strength of the irradiated CNFs films decreased while the elastic modulus increased. Moreover, the tensile strength of the film was reduced by 1.8% when the radiation dose was 5 kGy, while the elastic modulus increased by 15.1%. At this time, the mechanical properties of the film were the best. The barrier performance experiment showed that irradiation had no significant effect on the barrier performance of CNFs films, but the oxygen and water vapor transmission of CNFs films treated with 10 kGy gamma ray decreased by 6.2% and 4.1% respectively compared with the film not irradiated and the barrier performance of samples was the best at this time. In addition, gamma-irradiation reduced the hydrophilicity and thermal stability of CNFs films, but increased the crystallinity. An appropriate amount of 60Co γ-ray irradiation can increase the rigidity of CNFs films to a certain extent, and the other properties of the film are almost not affected. It is proposed that the CNFs films irradiated by 60Co γ-ray may have the potential applications in packaging.