Waterway grade of Hejiang river is low for a long time,which restricts the navigation capacity and navigation benefits.This paper establishes a one dimensional mathematical model to study the navigable water level and the length of shoal under the condition of hydropower stations’s operating,takes the channel regulation width and water level decrease ratio into account,and analyzes the feasibility and application conditions of the improvement of Hejiang river waterway’s level.In the end,the shoal length,channel regulation width and water level decrease ratio are chosen as factors to be determined for the optimization of waterway grade.The result indicates that the suitable waterway grade of Hejiang river is the fourth.