The invention discloses a Brillouin optical time domain analyzer relevant to a chaotic laser, which is an optical fiber Brillouin optical time domain analyzer made according to the chaotic laser relevant principle, the coherent amplification Brillouin scattered light, the temperature effect and the optical time domain reflection principle. In the analyzer, the same chaotic laser device serves as the local reference light source and the pump signal light source of the Brillouin optical time domain analyzer. According to the chaotic laser relevant principle, the chaotic laser has an ultra-wide frequency width; signal light and local light are relevantly processed to obtain a high spatial resolution, so that the reliability of the sensor can be effectively improved, the spatial resolution can reach the centimeter level, the number of pump photons entering the sensing optical fiber is increased, the signal to noise ratio of the sensor system is 10dB, and the measurement length of the sensor can reach 50km; and the same chaotic laser device is adopted to serve as the local reference light source and the pump signal light source of the Brillouin optical time domain analyzer, thereby solving the problem of locking a narrow-band detection laser and a narrow-band pump laser, and improving system stability.