In order to solve the problem of navigation-obstruction mechanism of large ships sailing in the reservoir tail reach and improve the shipping benefit of the three gorges reservoir，we planned the channel dimensions of three Gorges reservoir area downstream Chongqing Jiulongpo as 3.5 m×150 m×1 000 m.Under the new impoundment of three Gorges reservoir conditions，we check the designed lowest navigable level of navigation-reef river of the Three Gorges fluctuating backwater area，probe into the influence of regulation scheme on the designed lowest navigable level by a long reach one-dimensional flow model，and check the overall effect of regulation scheme.After implementation of the rock-blasting scheme，the channel under the designed lowest water level meets basically the planned standard except for Wangjiatan section，and the sectional hydraulic indices combination meet the 3 000 ton ships self-propulsion critical condition on the beach.