Using empirical orthogonal function (EOF) method,this paper discusses the charateristics of topography change on Nanhui Nan Shoal.It is concluded as follows:First, erosion or deposition occurs sequentially from east to west alongshore.Second, there is an equilibrium node at the transitional part between submarine slope and seabed.Shoal profile change to the upside of the node is oppsite to the downside,i.e. the upside eroded while the downside deposited, and vice versa. The elevation change is very large on submarine slope, but it is relatively small on tidal flat and on seabed.