Project Introduction: The monitoring system studied in this project obtains the temperatures at different positions of optical fibers in the composite submarine cable in real time through the Optical Brillouin Optical Time Domain Analyzer (BOTDA), and combines the submarine cable temperature field model obtained by finite element method modeling to calculate the submarine cable conductors. Temperature values; Combined with optical fiber disturbance detection and power quality monitoring, the system provides all-weather distributed monitoring of cable safety. The system will detect potential hazards and warn of damage in advance, providing technical support for detection errors and routine MA. The monitoring system also provides auxiliary functions such as visual display of temperature information and historical data management. This technology fills the technical gap in the lack of safety monitoring for laying submarine cables. This technology can obtain the temperatures at different positions of optical fibers in composite submarine cables in real time and calculate the temperature values of submarine cable conductors; it can provide all-weather distributed monitoring for cable safety, discover potential hazards and provide early warning. The system also predicts surrounding conditions and prevents anchoring. We are now seeking cooperation and providing technical support. In addition, the system can also install a current-carrying analysis module to improve cable efficiency, and can also install AIS in advance to warn ships around the cable to prevent anchoring. The system does not need to modify the buried submarine cable, and can complete system installation and safety inspection tasks without changing the cable structure. It has an early warning function for potential safety hazards of submarine cables. It changes post-accident emergency repair into pre-monitoring and early warning, which provides submarine cable fault detection and daily maintenance. It saves a lot of manpower and material resources, and so far, the indirect economic benefits created are more than 10 million yuan. This system fills the technical gap in the lack of safety monitoring for buried submarine cables. It is the first domestic implementation of submarine cables and overcomes the technical problem of safety monitoring for submarine optoelectronic composite submarine cables.