In order to solve the problem that temperature sensor laying is complex and maintenance cost is high in the large-scale, multi-point real-time temperature monitoring process, the temperature monitoring system based on Fiber Bragg Grating was designed and developed. Using wavelength selectivity by optical fiber diffraction grating,a function of temperature and wavelength was established. Temperature of the measured position was inversed by calculating the wavelength variation through the optical fiber Bragg grating. Due to environmental, materials and other factors, the spectral distribution and temperature changes do not satisfy linear relationship. Therefore, designed the spectrum correction algorithm was designed, and function curve fitting of wavelength and temperature was completed with a degree of fitting greater than 99.7%. Experiments used FB136L-IAC-proof oven, LPT-200 diode, and 1 550 nm optical fiber to detect 20 to 280 ℃ temperature range of multi-point in real-time. The results show that when the temperature is changed by 1 ℃, the corresponding center wavelength shifts about 0.04 nm to longer wavelengths. Compared with the test data from standard device, the error is less than ±0.3 ℃. Meanwhile, the spectral correction algorithm was applied to the system to further improve the uniformity and accuracy of the temperature detection. Because the system uses fiber-optic sensor network, it has a strong anti-electromagnetic interference capability. The diffraction grating can achieve precise measurements, so it has big dynamic range and high accuracy. The innovation of the system is to ensure high-precision measurements, while still satisfy large-scale, multi-point, high anti-jamming capability of rapid laying, and has a strong practical value.