Abstract: Due to the river channel process in the bridge reaches, there are great changes in the navigation channel conditions and impacts upon ship navigation. The Hanyang alternative bar in the Wuqiao waterway sustains the law of “erosion in flood, and siltation during dry season”. If the upward navigation span of the Wuhan Yangtze River Bridge is clogged by the 4 m isobath curve of the Hanyang alternative bar during a dry period, navigation obstruction takes place. Even if the water depth in the navigation openings meets the navigation requirements, the navigation channel in the upstream of the bridge bends seriously as a result of the siltation of the Hanyang alternative bar, which makes a difficult situation for upward vessels, thus an adjustment of the navigation openings or even dredge maintenance is needed. In this paper, a two-dimensional flow mathematical model and a ship motion drift model are firstly integrated to calculate the necessary widths for the upward vessels passing through the bend channel with different siltation morphologies of the alternative bar. Then the authors analyze the navigation obstruction mechanisms of the Hanyang alternative bar from the point of view of ship kinematics. The analysis results show that the actual bend fairway’s width in the upstream of the bridge does not meet the requirements for the safe pass of the typical ship when there is a heavy deposition along the Hanyang alternative bar, which is close to the bridge, and that it is necessary to take proper measures for the safe navigation of the upward vessels.