As a core infrastructure for marine energy transmission and communication, accurate route positioning of submarine cables is crucial for their laying, operation and maintenance. With marine development moving toward more complex environments, traditional acoustic and optical detection methods have limitations; magnetic detection, however, has gradually become prominent due to its advantages like strong environmental adaptability, forming an "acquisition-understanding-execution" trinity technical system. This paper reviews the technology from the aspects of technical system, method characteristics, environmental adaptation and development trends, analyzes the system, summarizes key technical characteristics, identifies existing challenges, and prospects development directions.