In this book structure and properties of nanostructured cellulose have been discussed. Besides, an impact of the structural parameters on physicochemical, chemical, biochemical, physical and mechanical properties of nanostructured cellulose materials was described. Cellulose is a widespread renewable natural polymer, which is widely used for the manufacturing of diverse materials and products. Being typical nanostructured polymer, cellulose contains nano-scale fibrils, crystallites, paracrystalline and non-crystalline domains, as well as nanopores. To characterize the supermolecular structure of cellulose, the primary structural parameters - paracrystallinity, crystallinity and amorphicity, microfibrillar angle, as well as parameters of porous structure should be determined. These structural parameters affect various physical, physicochemical, chemical and biochemical properties of cellulose materials. The equations were proposed that allow calculate various properties of the polymer on the base of determined structural parameters.