Abstract: River channel scouring and silting significantly influence internal force and deformation of segments in shield tunnels，which is a key parameter in design of shield tunnels across rivers.Based on the large diameter cross-river tunnel project of Nanjing Metro Line 3，the influences from variation of water level and the riverbed scouring and silting of a deep trough in the Yangtze River on the shield tunnel are analyzed in detail.Setting the 300-year scouring line and 100-year flood and dry water levels as working cases，the internal force and joint deformation of the segments before and after scouring are calculated based on the beam-spring calculation model.The results show that the change of water level has limited effect on the bending moment of shield tunnel segments，while the riverbed scouring reduces the internal forces of segments obviously，in which the maximum positive and negative bending moments decrease by 56% on average.The maximum bending moment and maximum opening of segment joint appear in case of flood level without scouring.The research results can provide reference for similar projects.