The submerged breakwater intended to be built in the north branch of Hechangzhou waterway located at deep water with more than 40 m depth and high local velocity,which makes the construction of the submerged breakwater difficult.Based on a three-dimensional hydrodynamic model,we analyze the changes of hydrodynamic structures in different stages of “gradually raise” construction sequence.The results show that surface slope of local water near submerged breakwater during the construction process is up to 3‰.With the advancement of the construction process,the main flow velocity and velocity gradient of deep water area are increasing gradually.Especially in the range of 30 m in front of the breakwater,the maximum vertical mean velocity and surface velocity are 1.85 m/s and 2.1 m/s respectively.The results can be used to provide reference for the adjustment of construction measures caused by local hydrodynamic changes during the construction of submerged breakwater in deep water,so as to improve the construction accuracy.