Taking the isolated rocks in Luziliang reach in the Three Gorges Dam as the research object,the falling of water surface and the squat of ships is demonstrated using analytic solution,mathematical model and simplified flume model tests.Considering the planning of the Yangtze River waterway and the trend of bigness ships,the reef blasting depth is determined.After project implementation,the channel has been broadened,and the channel maintenance and the sailing safety are guaranteed.The regulation effects are good.