High-resolution observations of celestial objects in astronomy using ground-based large-aperture telescopes are important for addressing fundamental scientific inquiries related to astrophysics and galaxy evolution. However, the imaging quality of ground-based optical telescopes is severely limited by disturbance arising from atmospheric turbulence. Hence, researchers are developing adaptive optical techniques to correct wave-front distortions caused by atmospheric turbulence and achieve near-diffraction-limited resolution in telescopes. One of the fundamental technologies within this area is sodium-beacon technology, which involves exciting sodium atoms at an altitude of 90 km to provide a reference for wavefront sensing in adaptive optics. In this paper, the development history of sodium beacons in China and other countries is first provided, followed by an introduction of new adaptive optical systems adopting sodium beacons. Additionally, the limitations of sodium beacons and the corresponding research issues are presented. Finally, this paper introduces new application areas of sodium beacons. Notably, sodium beacons are not only beneficial to astronomy but also to many related fields, thus indicating their broad potential in diverse applications.