The invention discloses a multi-wavelength Brillouin optical time domain analyzer which comprises a multi-wavelength laser device, a coupler, a probe pulse optical path, a continuous pump light path, a detector and a signal acquisition processor, wherein the probe pulse optical path comprises a probe pulse light modulation unit, a first erbium-doped optical fiber amplifier and a first circulator, and the continuous pump light path comprises a continuous pump light modulation unit, a second erbium-doped optical fiber amplifier, a second circulator, a Bragg grating and a polarization scrambler. The multi-wavelength laser device emits continuous light, and the continuous light is respectively input to the probe pulse optical path and the continuous pump light path through the coupler. By means of increase of the number of the wavelength of probe light and pump light, the multi-wavelength Brillouin optical time domain analyzer can increase the total luminous power of the entered optic fiber in the premise that stimulated Brillouin scattering is not caused and effectively improve the signal to noise ratio of a system. Meanwhile, the measuring efficiency is enabled to be improved, the measuring time is shortened for a certain sensing distance, and the sensing range is improved for a certain measuring time.