Abstract: Re:YAG-SiO₂ multicomponent glass fiber is fabricated by a molten core method, in which a Re:YAG is used as the core material and a quartz tube is used as the cladding material. It has the advantages of high doping concentration, high mechanical strength, and is easy to fuse with quartz fiber. Recently, the single-frequency fiber laser has been studied extensively based on the Re:YAG-SiO₂ fiber. In this paper, the development of the Re:YAG-SiO₂ fiber fabrication and the single-frequency laser technology based on Re:YAG-SiO₂ fiber in 1.0 μm, 1.5 μm and 2.0 μm were reviewed. The difficulties and challenges of Re:YAG-SiO₂ fiber fabrication and single-frequency laser based on this type of fiber were also given.