In recent years, narrow-linewidth fiber lasers have attracted extensive attention owing to their application in the fields of beam combination and gravitational wave detection. However, stimulated Brillouin scattering and transverse mode instability seriously limit the power scaling of narrow-linewidth fiber laser. At present, the approaches to improve the power of narrow-linewidth fiber laser mainly focus on the optimization of fiber laser system. In this paper, the research progresses in the ytterbium-doped silica glass fiber for narrow-linewidth fiber laser and amplifier are briefly introduced, and the future development trend of narrow-linewidth fiber laser technology are prospected.