Brillouin lidar is one of the important methods to detect ocean environmental parameters. Firstly, the basic work principle of Brillouin lidar system was introduced. Then, from the theoretical basis, three retrieval models based on the relationship between Brillouin scattering spectrum characteristics: Brillouin shift, Brillouin linewidth, and the combination of them, and ocean environmental parameters were introduced. Secondly, as the key technology of Brillouin lidar, several Brillouin spectrum measurement methods were introduced: the scanning Fabry-Pérot(F-P) interferometer, the edge detection technique, F-P etalon combined with Intensified Charge Coupled Device(ICCD), and multi edge detection technique.