The influence of daily unsteady flow regulation on the downstream channel is the main problem to be considered in the operation of Xiangjiaba Project.Based on the two-dimensional unsteady mathematical model,we analyze the influence of daily unsteady flow of Xiangjiaba on the navigation conditions of the waterway of Luoguotan reach,and select two typical daily regulating conditions and two flood discharge conditions to analyze the variation characteristics of water level,discharge and velocity in the reach of the river.The results show that,under two typical daily regulation conditions,the variation of water level from unsteady flow ship to Luoguotan is from 1.26 m to 1.46 m,and the maximum daily variation of water level under flood discharge condition is from 2.05 m to 2.96 m.The unsteady flow has a certain influence on the reach of the river.According to the current navigation standard,the maximum daily variation of water level is from 2.05 m to 2.96 m.Under four conditions,the hydraulic index of river reach can reach the navigable hydraulic index.The characteristics of unsteady flow under the dam and its influence on the waterway and port wharf should be observed prototype,accumulate practical experience,and provide the basis for further optimization of power station scheduling scheme and downstream waterway maintenance.