Based on the monthly mapping of the construction section of the deep-water channel of Yangtze River Estuary from 2016 to 2019 year and the observation data of floating mud under normal weather conditions during the flood and low season of the deep-water channel in North passage from 2016 to 2020 year,the transport characteristics of floating mud,the change characteristics of silt back and high-frequency depth are studied,and the fine dredging and maintenance plan of the channel is proposed.The results show that under normal weather conditions,the depth difference of high and low frequency depth in the flood season is larger than that in the dry season,and the thickness of floating mud in the middle part of the northern channel is much larger than that in the dry season,and the sediment quantity of the channel increases with the increase of the depth difference of high and low frequency depth.It is suggested that the fine-maintenance dredging scheme should be implemented first in flood season.After trial application,it can effectively reduce the interference of floating mud,high and low frequency depth difference and other changes on channel assessment measurement and channel maintenance dredging,and it improves the fine-management level of channel maintenance and dredging.