Abstract: Holocellulose nanofibers(HCNFs) had attracted much attention in the field of nanomaterials due to their typical "core-shell" structure and excellent properties. This review summarized the preparation methods of HCNFs and their application progress in the field of functional materials. There were various methods to prepare HCNFs, mainly including physical methods(such as grinding, high pressure homogenization, ultrasonic treatment) and chemical methods(such as acid hydrolysis, 2, 2, 6, 6-tetramethylpiperidine-1-oxygen radical oxidation and deep eutectic solvent treatment) at present. HCNFs had the characteristics of wide source of raw materials, easy chemical modification and good biocompatibility, which showed significant advantages in film forming, thermal stability, renewability and mechanical properties, and could be prepared into materials with different dimensions and application directions, such as composite films, functional nanopapers, aerogels, adsorbents, emulsion stabilizers, etc. Based on the above reasons, it showed great application potential in the fields of biomedicine, electrochemistry, sensing and adsorption materials. The composite films(nanopapers) based on HCNFs with high transparency, sensitivity, good flexibility and mechanical properties, and HCNFs-based aerogels with low density and high porosity were mainly introduced.