Creation of eco-friendly and high-performance nanocomposites has become one of the most widely concerned focuses. Regenerated cellulose aerogels (RCAs), the typical green sustainable 3D cellulose products, have numerous merits including large surface area, high porosity, low density, high mechanical strength, 3D network structure and abundant oxygen-containing groups, which make them ideal candidates as green matrices to support various active nanomaterials for the development of novel functional nanocomposites. Therefore, RCAs open up a new promising avenue to create novel enticing materials with desired and tunable properties. Also, it is of great significance to search exact modification or adulteration technologies to create RCAs-based nanocomposites for advanced applications. In addition, to make RCAs more applicable and valuable, a deep understanding of the relationship between the structure (mainly dependent on the dissolution, regeneration and drying techniques) and property of RCAs is also necessary. Here, this review article highlights recent advances in the field of RCAs-based functional nanocomposites. The synthetic processes and mechanisms and representative physicochemical properties are also emphasized. We hope that this review work could play a certain guiding role for the study and creation of green RCAs-based functional materials and stimulate a wider range of studies and collaborations, leading to significant progress in this area.