The invention discloses a long-distance submarine cable sea area safety monitoring system, which comprises a front-end monitoring station and a submarine cable remote monitoring center. The front-end monitoring station comprises a video acquisition module, a radar module, a satellite AIS reception module, a remote control module and a data transmission module. The video acquisition module is in communication linkage with the radar module and the satellite AIS reception module, and is used for obtaining image information of ships passing across the sea surface above a submarine cable sea area; and the radar module realizes a search function for ships in the long-distance submarine cable sea area, and can be linked with the video acquisition module and the radar module. The system can realize all-weather, all-directional and broad-coverage effective monitoring of the ships in the submarine cable sea area, and can carry out all-weather safety monitoring on sea surface moving objects with distance being larger than or smaller than 5 km under abnormal weather conditions of night and fog and the like.