Yangkou Port Yangguang Island is an important LNG receiving port in China,this paper analyzes the long-term dynamic changes of the tidal flat evolution,the erosion and deposition situation in the LNG terminal area,and the impact on the foundation piles of the terminal by comparing underwater topographic data from different periods.The results show that with the gradual completion of the artificial island and terminal supporting facilities,the Dahonggengzi sandbar on the northeast side of the artificial island has been moving westward year by year.The northern waterway continues to maintain a westward and northward extension trend.The head of the central waterway has slowed its westward extension,but shows a trend of continuous southward compression and widening.The LNG terminal area exhibits different patterns of erosion and deposition at different stages.In the early stage,it was mainly a micro-sedimentation state.After 2010,due to the impact of terminal construction,significant scour occurred around the A1 and B1 docks.By 2018,the terminal area gradually transitioned to a deposition state,and the sediment on the northern slope of the artificial island significantly increased.For the proposed A2 terminal project,a protection approach combining preliminary protection and post-construction protection with reserved scouring depth will be adopted to reduce the scouring rate of the pile foundation and prolong the service life of the pile foundation.