radial tidal sand ridge system with an area of more than 20000 km2 in the southern Yellow Sea is fanshaped and stretches from Qianggang toward the sea with a central angle of 160°The marine radial tidal sand ridge system is associated with a convergentdivergent tidal current fieldMore than 60 drilling holes reveal that an area of 3000 km2 of tidal sand strata in exists Jiangsu coastal plain on land,which is adjacent to the marine radial tidal sand ridge system and stretches eastward from Dongtai and is also fanshaped with a central angle of 130° The tidal sand unit lies on a transgressive coastal barrierlagoon unit with an erosional surface between them, and the latter unit is in turn lying on the Late Pleistocene stiff mud, with a longterm hiatus between them  The tidalsand unit is overlain by the littoral tidalflat unit and together they constitute the Holocene regressive succession The erosional surface at the bottom of the tidal sand unit may serve as a surface, below and over which a transgressive succession and a regressive succession exist respectively Paleocurrent study reveals that a paleo current pattern with a convergentdivergent tidal current field similar to the modern marine was present in the Holocene subaerial tidal sand strata Therefore, the subaerial tidal sand bodies may be inferred to be an ancient radial tidal sand ridge system that was formed during the Holocene regression, and gradually exposed and changed into land as the Changjiang and Huanghe deltas prograded Both subaerial and marine radial tidal sand ridge systems were formed in the same tidal depositional environment but at different development stages Thus, the radial tidal sand ridges in southwestern Yellow Sea should have been formed in the process of the Holocene regression  Mineralogical analyses demonstrate that the sediment sources of the subaerial and marine radial tidal sand ridge systems mainly came from the Changjiang River and the Huanghe RiverSediments of the Changjiang River were migrated from south to north in the earlier period,while sediments of the Yellow River were migrated from north to south in the later period.The tendency of mud and sand migrating has continued until today.  As the sealevel rise slowed down, the Jiangsu coastline has prograded seaward as the Changjiang delta expanded and the radial tidal sand ridge system in northern Jiangsu gradually exposed to landThis progradation was accelerated when the Huanghe River debouched in the north of the study area in 1128The convergentdivergent tidal current field has shifted its apex three times since the Holocene maximum transgression, from the apical area of the Changjiang palaeoestuary to Dongtai of the northern Jiangsu tidal sand area, and then to Qianggang It means that the radial tidal sand ridge system has also experienced three stages of development, and has changed its location from Chengdong to Dongtai, and then to Qianggang However, the radial tidal sand ridge system developed in the Changjiang palaeoestuary has not been found so far,which maybe due to the strong reworking of river currents