The invention relates to a multi-point temperature sensing system composed of Bragg gratings, which belongs to the technical field of optical fiber sensors. Its main structures include a pump source (1), an optical wavelength division multiplexer (2), an erbium-doped optical fiber (3) and the like. The invention uses a sinusoidal signal as a modulation signal, does not generate high-frequency interference, and has the characteristics of more reliable operation, high sensing precision, wide application range and the like.