Nanofiber-based forward osmosis (FO)/reverse osmosis (RO) composite membranes have garnered significant attention in the field of membrane separation. Their unique structure and performance characteristics have paved the way for new possibilities in membrane technology. These composite membranes leverage the high porosity and exceptional three-dimensional pore structure of nanofibers to efficiently retain solutes and enhance flux during the permeation process. This review focuses on highlighting the advantages of nanofiber support layers in FO/RO technologies, discussing methods for nanofiber fabrication, summarizing the recent applications of nanofiber FO/RO membranes across various domains, and offering insights into the prospects, application potential, and future development trends of nanofiber support layers.