The invention discloses a high-ultraviolet-reflectivity film based on bacterial cellulose and a preparation method thereof; the high-ultraviolet-reflectivity film is prepared by: using film, formed byelectrostatically spinning bacterial cellulose dissolved in an ionic liquid, as a base, and connecting nano bacterial cellulose particles, formed by high-pressure homogenizing, to the base by means of surface grafting; the high-ultraviolet-reflectivity film has ultraviolet reflectivity of >65% for wavelength of 266 nm when having an incidence angle of 15 degrees and has ultraviolet reflectivity of >85% for wavelength of 266 nm when having an incidence angle of 45 degrees. The high-ultraviolet-reflectivity film based on bacterial cellulose is prepared on the basis of bacterial cellulose by means of ionic liquid dissolving, electrostatic spinning, high-pressure homologizing, silane coupling agent modifying and the like; no high-toxic substances are involved in experimental materials and processes; the product is a natural organic macromolecular material having good biodegradability and meeting the environment protection requirement.