Since the impoundment of the Three Gorges reservoir,water and sediment to the downstream reach has changed,resulting in the process of river transformation on the Changjiang-Guanzhou river and erosion of the bed.Based on the latest prototype observation data of the reach after construction of the Gorges project,we know that the waterway after the Three Gorges reservoir is generally in the scour situation,especially the left branch.This situation exerts a great influence on the waterway shunt of the two branches,and thus further affects the main waterway conditions,and meanwhile influences the entrance channel conditions of the waterway downstream Lujiahe.Based on the above analysis,we predict the waterway variation trend,and think that the currently favorable waterway condition may change worse under the action of natural deterioration.The research result may serve as reference for the determination of the regulation indea and engineering design of this waterway.