In recent years，affected by the Three Gorges reservoir and river regulation project，the river boundaries and water and sediment conditions in the lower reaches of the Yangtze River have changed significantly. In particular，the erosion and deposition of Laohaiba reach have changed dramatically in the year，which has an impact on river flood control，shipping and shoreline utilization. In this paper，the characteristics of riverbed evolution in Laohaiba danger section are discussed based on the topographic measured data of nearly 15 years，and the influencing factors are studied. The results show that：1）the plane variation of Laohaiba reach is small，the isobaths of -10 m and -30 m near the south bank are basically stable，and the depth range of -50 m is expanded.2）The transverse variation of river cross-section morphology is small，and the longitudinal variation is large，showing a trend of narrow and deep development.3）The implementation of the rubble-throwing revetment project of Laohaiba has changed the range of erosion and deposition of the riverbed in different isobaths，and intensified the range of erosion and deposition of the deep trough. The variation of erosion and deposition near the bank slope is relatively small，while the range of erosion and deposition of the deep trough is large. The evolution of erosion and deposition from the Jiulong Port to Shiyiwei Port is the most intense. 4）There is a negative correlation between the erosion and deposition of the deep channel below -30 m of Laohaiba section and the flow of the upstream Datong station. At the same time，affected by the geological boundary conditions of the river channel，the river bed will still be in a state of erosion for a long time under the action of the centrifugal force of the bend flow. The research results can provide reference for the study of river channel evolution and bank slope protection in the rapidly changing river regime area.