Introduction   The 500 kV Fugang Line submarine cable route is the only high-voltage cable channel connecting Hainan Province and the mainland across the Qiongzhou Strait. Due to the rapid flow of water in the Strait., number of ships pass through, the fishermen have frequent activities, and fishermen′s random anchoring is serious. If the exposed or suspended cables are subjected to external forces, they will be bent and deformed. If the deformation is too large, the internal structure of the cable will be damaged and seriously lead to cable fracture.

    Method   This article discussed the use of Multbeam System to scan submarine cable routing terrain, according to the massive data collected in the past. The Kriging interpolation method was used to generate the DEM model and compared the elevation values of both. Analyzed the evolution of terrain and the trend of sand wave.

    Result   The Multibeam System has the characteristics of large data volume, small dot spacing and high precision in the analysis of submarine terrain scouring and micro-geomorphology evolution, which can well grasp the changing trend.

    Conclusion   For offshore structures with complex water flow and complex seabed topography, it is recommended to use a Multibeam System to regularly scan the surrounding terrain, master the trend of organic carriers, provide data basis for the protection measures of offshore structures and minimize the probability of damage to ensure normal operation.