The sand supply to Jiangsu coast was cut off after Yellow River shifted to north into the Bohai Bay in 1885,and then the outer channel of Lianyungang turned to an erosional environment.This paper is devoted to the evolution of erosion-deposition pattern of the area based on studies of changes in environment,topography,wave,coastal current,sand input and other environmental elements.It is found that 0.43kg/m3 of sediment supply is the lowest limit to profect the coast from erosion.Since 1973,the area has become depositional due to the input of large amount of the abandoned soil and sand from the harbor construction.However,the deposition is induced by human activities.It will be replaced by erosion as soon as the project ends.The erosional manner is beneficial to the Xuwei port and the ongoing dredging project for the 30 DWT channel at Lianyungang.