Enclosed electrical apparatus is an important component form of power transmission and transformation equipment in power system, which is more and more widely used in power system. Firstly, this paper summarizes the research basis of partial discharge location, that is, the study of partial discharge characteristics and the signal types of partial discharge. Then, the basic principles, advantages and disadvantages of various partial discharge location methods are emphatically analyzed. Including signal sequence comparison method based on UHF signals, signal maximum amplitude comparison method, signal time difference calculation method and signal space positioning method, and positioning method based on ultrasonic waves. Finally, the new progress of PD localization research and the direction worthy of further exploration in the future are expounded.