Abstract: During the construction of cross-river tunnels, the shield segments are under enormous water and soil pressure, and the design and construction are facing with major technical problems.In view of the maximum water pressure section of an underwater tunnel in Jiangyin reach of Changjiang River, a segment lining model was established by using the modified usage method and the beam-spring method respectively.The influence of different assembly methods on the mechanical properties of the segments under high water pressure is studied by adjusting the position of the capping block and the staggered joint angle.The results show that the calculation results of the modified usage method change smoothly, while the distribution trend of the beam-spring method calculation results is affected by the joints, and there is a sudden change around the position of the joints.The mechanical properties of the segment are greatly affected by the position of the capping block and the staggered joint angle.With the increasing of the staggered joint angle, the maximum axial force, bending moment and displacement of the segment change periodically with the central angle of the standard block as a period.During the construction, in order to prevent large displacement, it is necessary to avoid the overlap of the front and rear ring segment joints.The above results can provide a reference for the design of segment assembly in high water pressure shield tunnels.