Abstract: MIKE21 hydrodynamics module is used to study the hydrodynamics change caused by Zhoushan Green Petrochemical Reclamation Project.The sediment deposition and scouring process is studied in depth with the help of empirical equations.The research indicates that the tide current in the area of the project site is mainly alternating type, and the impact on general flow field is limited because the design has taken direction of current into consideration.However, the flow near the changed shore at the edge of the project site is not the same as before.The flip action caused flow speed changes at some places.The speed change of flow at those places has been controlled within the limit of 0.4 m/s, less than 35% of original speed.Change of overall flow speed is in the range of 0.03~0.12 m/s, 6%~12% of the original speed.Sediment deposit sites are mostly in the sea areas in front of the embankment, around embankment corner or in the south-east flow shadow and the north- west flow shadow.Some others are found in an island-surround semi-enclosed area.The scoured areas are found at some spots close to the embankment or in the flow flip area around the embankment corner.