The invention provides a large-range super-high temperature sensing system which comprises a composite optical fiber probe, a lens coupling structure, an optical fiber beam splitter, a coupler, a laser light source, a photosensitive tube, a fluorescence signal processing unit, a radiation signal processing circuit unit and a host computer, wherein the composite optical fiber probe is connected with the optical fiber beam splitter via the lens coupling structure; light emitted from the optical fiber beam splitter is connected with the photosensitive tube and the coupler, respectively; the coupler is connected with the laser light source and the fluorescence signal processing unit; the photosensitive tube is connected into the radiation signal processing circuit unit; the fluorescence signal processing unit and the radiation signal processing circuit unit are respectively connected with the host computer; the composite optical fiber probe comprises composite optical fiber and a temperature-sensing black-body radiation cavity at the end part of the composite optical fiber. By adopting the large-range super-high temperature sensing system, super-high temperature monitoring of a large range of 50-1800 DEG C can be achieved.