Abstract: The numerical simulation of segment joints of Nanjing metro shield tunnel was carried out with 3D FEM (finite element method). The deformation, rotational angle and bending stiffness of a segment joint under different working conditions were investigated, and the varying law of rotational angle and bending stiffness were discussed. In addition, the fitting relation between rotational angle of a segment joint and bending moment and axial force was obtained to provide a new way of determining joint bending stiffness. The numerical result shows that the bending stiffness of segment joints increases with the increasing of axial force, and the bending stiffness decreases rapidly and trends unchanged with bending moment increasing. Influence of axial force on joint bending stiffness weakens with the increasing of bending moment.