The local force and deformation of shield tunnel will be transferred and redistributed owing to the discontinuous segmental structure. This study develops quantitative evaluation index to explore the influence of the axial compression ratio, eccentricity, and longitudinal force on the assembly effect. A full-scale test is conducted on a single segment and staggered assembled segmental linings. First, the results show that the assembly effect has an obvious redistribution influence on the force and deformation of the segment. Second, the influence of eccentricity on the bending moment is much larger than that of the axial force. The stiffness between rings varied at different positions and the larger the stiffness difference, the more obvious the assembly effect. The results demonstrate that the design and mechanical performance of the shield tunnel under different embedded conditions can be optimized by increasing the longitudinal force, which moderates the assembly effect and ensures the structure reaches the highest bearing capacity.