The deepwater channel of Dafeng Port area in Yancheng Port is located at the northern edge of the radial sand ridges in northern Jiangsu,constructing a 100,000 DWT deepwater channel relying on west trough of Xiyang channel.The Dafeng deepwater channel phase I project of first and second stages is arranged the same scale for the construction.Backsilting characteristics and sources after Dafeng deepwater channel excavation are studied based on the measured flow,sediment and terrain data.The results show that the annual silting intensity of the second stage of Dafeng deepwater channel is 0.66 m/a,which is less than that in the first stage,mainly because of the onshore treatment of dredged soil.The temporal and spatial distribution characteristics of channel backsilting in the two stages are similar.The channel deposition intensity is high in the first four months after acceptance,and then it decreases,with slightly higher backsilting in winter than in summer.The backsilting in the channel inner section is greater than that in the outer section,and the high deposition area is mainly located on the west side of the Xiaoyin sandbar gully.The main reason is that the sediment sources in the inner section are relatively abundant,including sediment brought by the scouring zone of the outer sea,sediment scoured by Xiaoyin sandbar,and sediment diffused from temporary sludge throwing area.