The section of Xijiang from Jieshou to Zhaoqing is located in the Guangdong section of the Xijiang Shipping Main Line.The river shape is winding and varied,with locally dense shoals and reefs.Since the 1990s,after several regulations,it has been able to accommodate ships of 2,000-ton class.The 3,000-ton class waterway expansion and upgrading project was implemented in 2016,taking engineering measures such as dredging,removing the reef,and encrypting spur dike of the “Sitan” section(Jieshou,Panlong,Xintan,and Dule shoals)that obstruct navigation.Analysis of measured data and mathematical models shows that the engineering measures have unblocked the main channel,realizing navigation depth greater than 4.5m for the entire waterway.The water level of the “Sitan” section has decreased by an overall 0.20-0.49 m under different characteristic flow rates,with an average water surface gradient of only 0.013‰-0.053‰.The change in water flow velocity is between -0.23 and 0.34 m/s,and the angle between the water flow direction and the main axis of the channel in most sections is less than 10°.The navigation conditions of the channel have been significantly improved,and the management goal of 3,000-ton class channel has been basically achieved.The research results can provide references for further capacity expansion and upgrading of the river section or for channel regulation under similar characteristic conditions.