The invention discloses an ultraviolet reflective material based on nanocrystalline cellulose and a preparation method of the ultraviolet reflective material. The ultraviolet reflective material is prepared by taking polyacrylonitrile electrospun fibers as a base material, and grafting the nanocrystalline cellulose to the surface of the base material by using a surface modification process, wherein the reflectivity of the ultraviolet reflective material for ultraviolet rays with the wavelength of 280nm when an incident angle is 30 degrees is greater than 70 percent, and the reflectivity of theultraviolet reflective material for the ultraviolet rays with the wavelength of 280nm when the incident angle is 45 degrees is greater than 90 percent. According to the ultraviolet reflective material disclosed by the invention, a hydrogen bond is formed by using active hydroxyl on the surface of the cellulose and hydrogen atoms with high electronegativity in a molecular structure of the polyacrylonitrile electrospun fiber, and a stable cross-linking structure is formed inside a connecting material structure; according to the preparation method disclosed by the invention, a membrane materialis prepared by using an electrospinning technology and the like, so that mass use of volatile pollutants such as an organic solvent can be avoided, and environmental protection and sustainable development are benefited.