In order to restrain the system temperature shift and the strain of optical fiber in the distributed optical fiber Brillouin temperature sensing system which is based on the demodulation method with the intensity of Rayleigh scattering and Brillouin scattering, a novel method, which uses the latest known temperature curve to demodulate the test temperature curve, is proposed and the experimental system is designed. The experimental result shows an excellent agreement with the theory, and it indicates that the Brillouin temperature sensing system based on the new demodulation method can improve the temperature precision, stability, and reduce the cost of the system efficiently. Moreover, the temperature test precision of the system reaches ±0.09 K.