Abstract: The radial sand ridges (RSRs) along the coast of Jiangsu Province are a rare form of tidal sand body. Some inferences have been made on the hydrodynamic mechanisms of radial sand ridges formation;however,opinions on their formation time and sediment origin source differ. In this study,the formation and evolution of radial sand ridges were simulated by a long-time-scale dynamic geomorphological model. The results showed that the convergence and divergence of sand flow field outside the coast of Jiangsu province existed independently without the influence of seabed topography. In different initial topographies,the radial "channel-sand ridge" geomorphological pattern is formed by tidal power in around 150 years as long as there is sufficient sediment supply. Because the abandoned Yellow River flowed northwards 150 years ago,the Yellow River underwater delta continues to be eroded. The radial sand ridges are the result of redistribution of different sediment sources from convergence and divergence flow and are the products of dynamic-sediment-topographic interaction.