Objective To extract nano-cellulose from agricultural waste - coconut litter, and prepare a high-strength and transparent film using it. Methods Nano-cellulose was obtained by chemical treatment, grinding and ultrasonic extraction and characterized by FTIR and XRD. After vacuum filtration, the microscopic morphology, transmittance and mechanical properties of the film were characterized by SEM, UV- ultraviolet spectrophotometer and universal strength testing machine. Results The results showed that nano-cellulose was extracted entirely from the coconut litter, and its crystallinity reached up to 56% . Furthermore, the performance of the film prepared from the nano-cellulose was good, which an elastic modulus of 3.3 GPa, a tensile strength of 126.4 MPa, and a transmittance of 88%. Conclusion Coconut litter could be used as a extraction source of nano-cellulose, and could be used for preparation of high-strength transparent films and other functional packaging materials.