The invention provides a super-continuum-spectrum light source output apparatus of a resonant cavity. The apparatus comprises an optical resonant cavity, an ytterbium-doped fiber, a laser device, an acousto-optic modulator and a tapered fiber, wherein the ytterbium-doped fiber, the laser device, the acousto-optic modulator and the tapered fiber are arranged successively in the optical resonant cavity. The optical resonant cavity is used for controlling an oscillation function in a light beam cavity and outputting a super-continuum-spectrum light source; the ytterbium-doped fiber serves as a gain medium of the super-continuum-spectrum light source; the laser device serves as a pump source of the super-continuum-spectrum light source; the acousto-optic modulator is used for outputting a laser pulse at a specific frequency; and the tapered fiber is used for enhancing a non-linear effect and the energy in a short-wave direction of the super-continuum-spectrum light source. According to the super-continuum-spectrum light source output apparatus, the structure of the existing super-continuum-spectrum light source output apparatus is simplified; the spectrum widening is realized under the circumstance of low pumping power; the cost is lowered; and the light-light conversion efficiency is high.