Abstract: To address the limitation of traditional cross-sectional scanning methods for submarine pipelines, which only capture localized cross-sectional information and struggle to detect continuous axial deformation features, this paper proposes a data fusion method based on acoustic sub-bottom profiling that integrates both cross-sectional and longitudinal scanning. By deploying survey lines both perpendicular and parallel to the pipeline axis, and utilizing a parametric sub-bottom profiler combined with a high-precision positioning system, the method enables the simultaneous extraction and comprehensive analysis of multiple parameters, including pipeline inclination, cross-sectional ellipticity, longitudinal elevation deviation, joint misalignment, and external environmental anomalies. Field tests conducted on a water pipeline in the South China Sea successfully identified five types of typical anomalies, including pipeline tilt, depressions, obstacles, and upheavals. The results verify the effectiveness and engineering applicability of the proposed method for diagnosing submarine pipeline stability, providing a reliable technical approach for continuous deformation monitoring and safety maintenance of long-distance submarine pipelines.