The reach of Wanzhou Guandaoqi is wide alternating with narrow,which is the typical representative reach of the Three Gorges regular reservoir area.Based on the bulk of measurements,this paper analyzes the evolution of river bed since the impoundment of the Three Gorges reservoir.The result shows that the Three Gorges regular reservoir area is not the whole river siltation,but presents“point”or“segment”decentralized distribution of siltation.Channel geometry shares a close relationship with sedimentation accumulation distribution and siltation intensity,and siltation plane is mainly distributed in wide reaches,bend convex bank below,deep trough and other parts.Siltation intensity in river gully section is relatively large,but it is smaller and even scoured in small narrow section.