There are two main reasons which make the serious mudding and pollution in Nantaiwu beach.Firstly,in front of Nantaiwu beach water area,the wave is small and the trend is weak;secondly,Jiulong river and coastal land sewage water have a direct and great impact on the beach.Facing with complex external boundary conditions,this study integrates coastal dynamics,ecology,environmental science and other disciplines,considering the needs of urban sewage drainage and landscaping,then analyzes the current situation and mechanism of mudding.From technical,economic and ecological views,this study demonstrates the feasibility of regulation scheme,and innovatively applies siltation reducing shield into engineering design.