Xiaonanhai beach land in Chetingqi waterway is the key navigation-obstructing channel due to its shallow,chaos and rapids flow.Based on recent investigation data，the flow-sediment property，variation of depth contour，thalweg and typical cross sections are studied.Results show that during recent decades,the plane form of Xiaonanhai beach land was steady,but local deep groove was significantly changed due to the remediation project.After the impoundment of the Three Gorges Reservoir,Xiaonanhai beach located at the fluctuating backwater area at the dry season.Since the small discharge at the dry season results in weak sediment-carrying capacity,and the upstream Xiangjiaba dam barriers a lot of sediment,siltation is unobvious,so its evolution is still induced mainly by remediation engineering measures.