To solve the problem of serious extra-dredging by the large self-propelled trailing suction hopper dredger in channel dredging construction,especially in the large-span deepwater channel dredging construction,we adopt RTK non-tide technology,multi-beam sounding system and layered excavation technology in the dredging engineering of 300 000 DWT main channel of Meizhou bay by the large self-propelled trailing suction dredger the Long Whale 6 to explore the technologies in precise control of dredging depth as well as the management measures by analyzing the tidal data,dynamic hierarchies and measurement results,especially by comparing and calibrating the tidal observation station data with GPS RTK tidal observation data.