The origin of the Radial Sand Ridges in the southern Yellow Sea has been a controversial issue since they were discovered. The M2 tides and tidal currents over the Bohai Sea, Yellow Sea and East China Sea at present and at around 7000 a B. P., 6000 a B. P.,3800 a B. P., the 8th and 11th centuries A. D. were simulated with a two-dimensional tide model. The sediment transport field and sea bottom erosion-accretion pattern in the Paleo-Changjiang River Estuary and its adjacent area at the transgression maximum of Holocene were also calculated. The results showed that the radial tidal current field in the southern Yellow Sea has existed since at least the transgression maximum of Holocene, and is very stable. The formation and existence of the radial tidal current field has no relation to the local bottom topography and the Qianggang Bay outline. The radial tidal current field formed the Radial Sand Ridges in the southern Yellow Sea so they have tidal origin. At the transgression maximum of Holocene, sediment from the Paleo-Changjiang River filled the Paleo-Changjiang River Estuary, was the material source of the Changjiang Delta, and formed the primitive Radial Sand Ridges under the effects of tidal currents which transported sediments from sea to land. The formation of the Radial Sand Ridges in the southern Yellow Sea during the Holocene was mainly divided into five stages, and the inevitable result of the continental-oceanic interaction process in the area of the Changjiang Delta and northern Jiangsu littoral plain at a certain geological history stage.