Abstract: In view of the need to choose route and landing points for subsea pipeline of the Tianjin Nangang Industrial Zone, and the relocation project of Boxi Hydrocarbon Processing Plant, numerical model is used to carry out hydrodynamicm numerical simulation of the whole region (the whole Bohai Sea) to calculate the tidal boundary of the small region (the Bohai Bay) and make hydrodynamic numerical simulation for the small region. Meanwhile, sediment transport model is introduced to simulate the sediment movement in the Bohai Bay, and finally the erosion and sedimentation pattern of deposits in the estuary area in New Ziya River under the condition of flood discharge are figured out. Analysis in the paper shows that it is feasible for submarine pipeline to land in the estuary area in New Ziya River, but the pipeline route and landing point should be away from the area with a erosion depth of more than 1 m, and on this basis, two recommended solutions are put forward.