FBG-HT high temperature sensor uses Regenerated Bragg Gratings (RBGs) as sensing elements, which can be used for temperature measurement of the range from room temperature to 1000 ℃. The Regenerated Bragg Grating (RBGs) is obtained by annealing the common I – type UV writing FBG. Its reflectivity is stable, and its reflection wavelength has a good linear relationship with the temperature to be measured.