Spatial resolution is an important performance parameter in Brillouin optical time-domain reflection(BOTDR) technique. Affected by the acoustic phonon lifetime in the fiber, the spatial resolution of the Brillouin optical time domain reflectometer used in the engineering field is more than one meter, which can meet most engineering needs. With the continuous expansion of application scenarios, the requirements for the spatial resolution of Brillouin optical time domain reflectometers in fields such as special structural deformation monitoring and precise positioning of pipeline deformation are also increasing. This study introduces the structure of BOTDR and illustrates Two types of methods to improve the spatial resolution of BOTDR. Additionally, important progress in BOTDR sensing for decades are reviewed. On the basis of the relatively mature existing hardware, the method of improving the spatial resolution in the future will develop in the direction of improving the software processing algorithm and combining various signal processing algorithms.