The present invention provides a method for producing laser used directly as a frequency standard of optical frequency, comprising: a collimated atomic beam used as laser gain medium; the laser gain medium being put in vacuum; before the particles of the laser gain medium entering a laser resonant cavity, a laser device controlled independently providing pump laser irradiation to produce an inversion of atomic population number between energy levels of the particles of the laser gain medium for achieving cavity mode frequency line width Γcavity of longitudinal mode of the laser resonant cavity larger than frequency line width Γgain of gain of the used laser gain medium. And the frequency line width of the laser outputted used by the laser device contracted by the present invention can attain less than 1 Hz and the outputting laser frequency is very steady. So the laser produced by the present invention can be used directly as a quantum frequency standard of optical frequency.