Abstract: Sedimentary features of tidal-bore deposits,evolution and resultant sedimentary sequence of main channel and tidal flat in the Qiantang Estuary are studied in detail by analuses of time-series satellite photos,and sedimentological and geochemical characters of a 4m high crop.The wide and shallow channel at the bore-affected reach shifts rapidly under intense interaction of tidal flow and river runoff.There is channnel evolution cycle of ~20 years linked to the decadal alterations of dry and wet periods in the catchment.On the vertical facies association of tidal channel-flat system,the lower section is a typical tidal-bore deposit at the main channel and the lower tidal flat,characterized by thick massive sandy beds with well developed soft-sediment deformation structures.The upper section is tidal rhythmite at the higher tidal flat,typical of mud couplets and spring-neap tidal cycles of tidal origin.The middle tidal-flat facies bears both sedimentary features of tidal-bore deposits and tidal rhythmite.C-M diagram and probability cumulative curve are useful to differentiate tidal-bore deposits from tidal sandy/muddy deposits.There is a general trend of higher ratios of Si/Al,Zr/Al and Ti/Al in tidal-bore deposits,and Fe/Al and Mn/Al in tidal rhythmites,which is mainly related to elemental behavior and selected sorting of hydrodynamic.Elements of Si,Zr and Ti majorly present in quartz and heavy minerals are therefore abundant in the higher energy depositional environment,while Fe,Mn elements which can be easily absorbed by clay minerals are consequently enriched in the lower energy sedimentary environment.