According to the historical data and recent measured data of Wuzhou Hydrological Station of Xijiang River Control Station，based on the analysis of the variation characteristics of Wuzhou design water level，this paper calculates the design flow and downstream design water level，and the design water level before and after the project by the mathematical model. Considering the influences of riverbed undercutting，tidal action，engineering dredging and other factors under the dam of the hub，this paper calculates and analyzes the design lowest navigable water level of Wuzhou Hydrological Station for the 3000-ton waterway project，so as to provide reference for setting relevant water levels for nearby project construction and similar waterway regulation.