Abstract: In order to achieve accurate temperature measurement in complex environments such as high corrosion, high radiation, and strong electromagnetic interference, a high-sensitivity all-fiber temperature sensor based on the sensing multi-wavelength Brillouin fiber laser (MBFL) and reference MBFL was designed and tested.The relation between the frequency shift of Brillouin scattering light and the temperature variation was analyzed theoretically and experimentally, the change in temperature was measured according to the frequency shift of the microwave signal obtained by outputting the Stokes laser signal pair beat frequency. The 10th-order Stokes pair was injected into a photodetector, which was selected by a tunable optical filter (TOF) with bandwidth of 0.1 nm.Furthermore, the accurate measurement of the temperature around the sensing MBFL could be realized. Results show that the temperature sensitivity is 10.829 MHz/℃ through beat frequency detection of 10th-order Stokes pair. And the measured temperature error is about 0.138 ℃ under the temperature variation of 40 ℃.