Taking the offshore artificial island project of Qiongzhou Strait’s white sand shoal as the research object, on the basis of the analysis of the measured data, we establish the tidal current numerical model based on unstructured grid, and analyze the dynamic variation characteristics of the flow field before and after the engineering. Using the model of suspended load and the model of the bottom sand, we predict the characteristics of the terrain evolution after implementation of the engineering, research the impact of dynamic changes in the water surrounding of Ruyi island project, and forecast the sediment scouring of the engineering sea area.