Based on analysis of topographic and hydrological data,we run an extended analysis of the characteristics of the riverbed evolution as well as the navigation obstructing at the Heishazhou Southern Waterway downstream the Yangtze River.The thought of waterway regulation is put forward.It shows that the change of erosion-deposition variation is relatively large when encountered flood years.The left channel scours and the middle and lower of right channel silt.The main reasons are that the overbank flow in the transition section of the channel increases during the flood period,division ratio of left channel increases along the way but right channel decreases,the central bar of the South channel bounded water flow limitedly,sediment transporting capacity in subcritical flow area of the right channel is insufficient and the scouring is not sufficient after the flood season.The basic idea of channel regulation should be to stable the favorable terrain pattern,intercept the overbank flow,limit the further development of the left channel erosion,and enhance the scouring of the right channel of the South Waterway.