•A new avenue for the fabrication of cellulose film.•The cellulose film was highly transparent (over 90%) and weakly hydrophilic.•The degradation half-life of cellulose film was 20 days.•The flexible electroluminescent device had been constructed by the cellulose film. Developing green substrates based on cellulose to substitute synthetic plastics meet the requirement for the sustainable future. However, cellulose-based substrates supporting for building electronic devices are usually opaque and highly hydrophilic, which ultimately limits the performance of optoelectronic devices. Herein, we report a new avenue for fabrication of highly transparent, weakly hydrophilic and biodegradable cellulose film. The acquired cellulose film not only has high transparency (over 90%), but also displays weak hydrophilicity (∼79° of initial water-contact angle) and still remains 3.5 MPa of tensile strength after soaking for two days in deionized water. Additionally, the degradation half-life of cellulose film is 20 days, and the cellulose films also have better thermostability. Moreover, the flexible electroluminescent devices have been successfully constructed by using this cellulose film as a green substrate. This novel strategy will greatly enrich the applications of cellulose films for next generation green electronics.