According to the shipping and freight volume forecast of the Yangtze Estuary,in order to meet the national development strategy of Yangtze River Economic Zone,navigational channel regulation in the south passage should be implemented as soon as possible.The recent river regime variations,morphology evolution trends and navigation-obstructing properties of the south passage and adjacent waters are analyzed. Regulation principles are proposed that channel regulation,river regulation and environment protection should be associated,cooperated and developed mutually in the region.At the same time,the regulation approaches such as“current limitation,shoal protection,channel stabilization”and“water diversion,depth increase,siltation reduction”are proposed.Finally,the general schemes of the south passage navigational channel project are proposed based on the preliminary study.