The inlet sediment discharge rapidly decrease as a series of hydro-hub projects working in the mainstream and tributary stream of the Yangtze River after the operation of the Three Gorges Reservoir,leading to some differences on the changes of the channel condition compare to research achievements in the argumentation stage.Based on the measured channel data from 2008,we analyze the navigation condition changes of permanent backwater zone and fluctuating backwater zone and the main reasons in the Three Gorges Reservoir.The results show that the sedimentation in some reach sections should be focused on its impact on the main channel width in the permanent backwater zone.The gravels motion and temporary deposition in the main channel will lead to a shortage of the navigation depth in the falling stage,and the navigation problem in the fluctuating backwater zone also will involve the complex flow patterns occur in the falling stage.