In recent years, with the continuous improvement of people"s awareness of environmental protection, bio-based materials are receiving more and more attention. As an emerging bio-based nanomaterial, nanocellulose has excellent mechanical properties, surface chemical modifiability and other characteristics, which shows great potential in many application fields. However, nanocellulose is a highly flammable material, which greatly limits their applications. Thus, the construction of flame-retardant nanocellulose materials is beneficial to expanding its application areas. This paper mainly introduces common methods for preparing flame-retardant nanocellulose based materials, including intrinsic flame-retardant nanocellulose materials and flame-retardant nanocellulose-based materials with additives. Several major types of flame-retardant nanocellulose based materials (membranes, aerogels, filament, etc.) and their applications are summarized, and the future development directions of flame retardant modification of nanocellulose are prospected.