Through observation data insitu for years and theory analysis as well as mathematics model calculation and physics model test,the study results show that:after the Three Gorges Project operation,the regime of river in the dam area will tend to the development of a smooth and slightly meandering single trough;the long term normal diversion of the hydropower plants may be secured by rational arrangement and operation of desilting bottom outlets;the navigation flow conditions can be or basically satisfied through reasonable arrangement of division dikeand position of its head;the primary measure for solving sediment accumulation in the upstream and downstream approch channels is "flushing sediment by moving water" and supplementing with machine digging.