The present invention relates to a method for preparing nanoparticles by using a laser, the method preparing nanoparticles by emitting a laser beam at a gas mixture comprising a material gas and a sulfur hexafluoride (SF6) catalyst gas, thereby having effects of improving production yield and saving energy according to the improvement in production yield. In order to solve the problem of a low production yield in a conventional method for preparing nanoparticles by using a laser, the present invention prepares nanoparticles by emitting a laser beam at a gas mixture comprising a material gas and a sulfur hexafluoride (SF6) catalyst gas, thereby improving the production yield of nanoparticles by means of the catalyst gas. Particularly, in order to remedy the problems of environmental damage occurring due to the generation of a material gas, which is an unreacted toxic gas, since the production yield of nanoparticles is low in a conventional preparation of nanoparticles, and of a system becoming complex and of high costs when recovering and reusing the material gas to be discarded, the present invention increases the reaction yield of a material gas by emitting the laser having a wavelength with excellent energy absorption at a gas mixture of the material gas and a catalyst gas, thereby having an effect of saving energy.