To investigate the natural backfilling characteristics of submarine pipeline trenches in complex marine environments, field monitoring of the backfilling process was conducted in the target area. Based on detailed geological data collection and analysis, multi-beam bathymetric surveys, near-bottom current velocity and direction monitoring, and sediment grain size analysis were carried out. This allowed for a clear understanding of current distribution patterns, sediment physical properties, trench morphological changes, and backfilling rates within the monitored area. Through systematic processing and analysis of the field monitoring data, this study not only deepened the understanding of the dynamic processes of natural trench backfilling but also provided valuable references for future field monitoring and the optimization of submarine pipeline trench design.