The 3 μm laser plays an important role in the laser medicine. Owing to the potential of fiber laser,the research on 3 μm fiber laser has great significance and value.The principle and research progress of the 3 μm fiber laser doped different rare earth ions are summarized,and several ZBLAN fiber lasers doped different ions are introduced.At the end,the faced problems of the 3 μm fiber laser are analyzed,and development tendency in the future is pointed out.