The spatial resolution of the large ground-based optical telescope is far below its diffraction limitation because atmospheric turbulence distorts light waves from the observed space objects, which is a critical scientific and technological problem to be solved urgently. Using sodium beacon laser to excite sodium atoms in the upper atmosphere at an altitude of 80～105 km can create a high brightness sodium guide star, which can be used as a beacon to detect the wavefront aberration caused by atmospheric turbulence. As the wavefront aberration can be corrected by using adaptive optics system, the imaging resolution of large ground-based telescope will be significantly improved to be near its diffraction limitation. The development of sodium beacon laser is described in detail, especially the micro-second pulse sodium beacon laser with spectral format matched to the mesospheric D2 line developed in Research Center for Laser Physics and Technique, TechnicalInstitute of Physics and Chemistry, Chinese Academy of Sciences, as well as its successful application in some large ground-based optical telescopes.