Based on the topographic data of different project stages of the Yangtze estuary deep waterway project,this paper quantitatively analyzes the scouring and deposition thickness of field in the north-channel spur dikes.Analyzing the differences between the north and south field of spur dikes in different stages affected by the progress of the project,we know that it deposits annually,more in the flood season and less in the dry season;the deposition thickness on the north side is more than that on the south side.The terrain changes of main channel and spur dikes fields are great before 2010,and the main channel tends to be stable,with a slow change,while the dam continues depositing after 2010.