Abstract: Under the dual action of upstream runoff and downstream tidal current, the hydrodynamic conditions and riverbed evolution are complicated in Fujiangsha section of the Yangtze River Chengtong reach. The south bank of the proposed Zhangjing cross Yangtze River passage is near the Shizi Harbor of Zhangjiagang City, and the north bank is between Xinliuzhu and Xiashi Harbors of Jingjiang City. The river-across project crosses the Fujiangsha sandbar and two channels that envelope the Fujiangsha sandbar. According to Plan A (crossing the channel at right of Fujiangsha sandbar), an under-river tunnel is employed. As to cross the left channel, there are two choices named A1 and A2. A1 is building a bridge in the upper reach, A2 is building another under-river tunnel in the lower reach. This study focuses on the analyses of the stability of the shoals, channels, thalweg, riverbed profiles, and the variations of riverbed erosion and deposition. Based on the comprehensive consideration of the riverbed morphology, the plan of “A+A1” is chosen. This research can provide a technology basis for engineering design and decision-making.