The hydrodynamic conditions of Modaomen Estuary are complex and the wave action is obvious.However,There is relatively little research on the residual currents characteristics in Modaomen Estuary under the influence of waves.This article is based on the SCHISM model and establishes a two-dimensional wave-current coupling numerical model.By comparing the characteristics of estuarine residual current in estuaries with and without wave influence,the impact of waves on the residual current is analyzed.Qualitatively analysis is conducted on the evolution characteristics of No.4 Jiaobei Sand from the perspective of residual current.The results show that the residual current force in the west branch of Modaomen estuary is relatively strong,and the residual current at the exit of Longshiku waterway on the west side is relatively small.Near the No.4 Jiaobei Sand,wave action is more obvious,and the residual current force is somewhere in between.Direction of residual current has a great change under the action of wave.Under the action of the strong residual current from the west branch and the wave lifting force,the ridge line of No.4 Jiaobei Sand has a tendency to deflect clockwise to the west.