The flow level comparing method and the stable waterway depth estimating method were adopted in the fine reach to research the water depth that can be reached when this river is under the influence of factors such as flow,slope,and bed roughness.Furthermore,according to the planned ship type and the current situation of the ship type at the watershed of Xijiang river,the dimension standards for constructing a level-4 navigation channel was put forward,and the feasibility of constructing a level-4 channel at this reach was comprehensively analyzed.