Abstract: The current filed and sediment movement around the Dayangshan island before and after a reclamation project is simulated using the three-dimensional ocean numerical model FVCOM, and the variation of tidal current and sediment distribution is discussed. Results show that after the reclamation, the maximum of flooding current and ebb current weakens and sediment concentration decreases within 0.26 km offshore west and southeast of the project area, while no obvious change of tidal currents and sediment distribution occurs further; Southeast of the project may have weak sedimentation accumulation, and sediment erosion may occur west of the project.