Abstract: In this paper, the research progress of single-frequency fiber oscillators are introduced in the terms of wavelength expansion, the development of single frequency fiber amplifiers are introduced in the terms of power scaling. Besides, the research achievements of 1 μm-band high-power narrow-linewidth fiber laser are summarized based on the techniques of generating narrow-linewidth seed sources. Then the development trend and main challenges of high-power single-frequency and narrow-linewidth fiber laser are analyzed. The key technologies of high-power narrow-linewidth fiber laser are summarized and discussed. Finally, applications in various fields based on the current development status of high-power narrow-linewidth fiber laser are introduced.