Based on the analysis of the natural conditions of Quanzhou Bay,this paper studies the impact of Xiutu artificial island on the hydrodynamic and sediment environment before and after its constraction by mathematical model from the aspects of hydrodynamic force,flow pattern,erosion and deposition.The results show that after the completion of the artificial island,the tidal capacity will be reduced by about 2%,which is in line with the flow pattern around the artificial island,but has some impact on the local flow field;some shoal sand sources will be solidified,and the macroscopical scouring and silting effects can be controlled.It can provide reference for the development and protection of similar projects.