This article establishes a two-dimensional numerical model for the Wenzhou Nanguan Island Wharf Project，and analyzes and studies the tidal current field in the sea area near Nanguan Island before and after the project construction，as well as the distribution of erosion and sedimentation in the project area.The research results indicate that overall，the average flow velocity of the rising and falling tides in the waters near the project varies within 0.02 m/s，while the flow velocity and direction in other surrounding waters have not significantly changed.Due to the impact of local engineering，sedimentation has occurred in the surrounding sea area of the dock.The planned 100,000-ton dock front has a maximum sedimentation volume of 89,000 m3，the entry channel has a sedimentation volume of about 73,000 m3，and other water areas within the port have a sedimentation volume of about 58,000 m3.Under the condition of a 50 year return period of 12 hours of heavy wave action towards the ESE，the planned siltation amplitude in the port area is within 0.32 meters，and the total siltation amount in the port area is about 58,000 m3.