The water conservancy characteristics and flood safety of seagoing rivers are mainly affected by tide current and sediment in the sea areas.Taking a port project in Hebei province as an example,this paper established a twodimensional model of tide based on Mike21,SWAN wave model.Large,medium and small nested models were used in calculating the changes of tide level and velocity in the sea area and in the estuaries of two seagoing rivers before and after constructing the project.By calculating the changes of tide level,current speed and sedimentation in the sea area and the estuary of two seagoing rivers near the port before and after constructing the project.This paper aimed at analyzing and discussing the influence of port construction on the hydraulic characteristics and flood safety of the two seagoing rivers.The calculation results showed that the construction of the project had little influence on the design flood control（tide）water level of the rivers,and had little influence on the velocity and flood levels of the Douhe River Estuary and the Shahe River Estuary.Finally,It concluded that the project had little influence on water conservancy characteristics and flood discharge safety of the two rivers.It provided a thought to analyze the influence of the port project construction on seagoing rivers and compile flood control impact assessment reports of similar rivers.