A fiber Bragg grating multi-point temperature sensing system comprises a fiber sensing cable package and a plurality of clamping devices distributed along an inner surface of a wall in a circumferential direction for securing the fiber sensing cable package. The fiber sensing cable package comprises a fiber Bragg grating based sensing cable comprising at least one optical fiber, a plurality of Bragg gratings inscribed in the optical fiber, and a fabric layer and a sheath tube surrounding the optical fiber. The multi-point fiber temperature sensing system comprises a light source for transmitting light to the Bragg gratings based sensing cable package, and a detector module receiving reflected signal. Each clamping device comprises a radiation tee and defines at least one mounting hole for securing the fiber sensing cable.