Based on the historical bathymetry data of the south channel of the Yangtze River estuary,and water depth of the fixed cross-sections for four times every year since 1998,we analyze the process of formation,development and erosion process for Ruifengsha,focusing on the influence of Ruifengsha’s change on the channel volume,wetted cross-sectional area,and cross-sectional shape at the south channel during recent decade.The results show that: 1)In recent years,the upper part of Ruifengsha has been in the stable status,and the lower part has gradually disappeared,which is caused by human engineering and disordered sand excavation.2)Ruifengsha’s changes have significant impacts on the south channel.There is an inseparable relationship between Ruifengsha’s changes and the phenomena such as the cross-sectional area keeps unchanged at the upstream,and it obviously decreases at the downstream of the south channel,the channel volume constantly increases,the deep channel deposits,becomes shallow,and turns to shore.3)We should take positive measures to diminish unfavorable influences.