Abstract: A criterion for seismic safety for immersed tunnels is important for their design. The nonlinear analyses of the materials and the contact are important for simulation of the nonlinear behaviors of joints using the finite element method. To simplify the calculation, an adjustment factor is introduced to modify the judgment condition in the contact algorithm, with consideration of the nonlinear contact between boundaries. The nonlinear behaviors of Gina gasket are also taken into account. By modeling, the axial stiffness, the flexural stiffness and the coupled shear stiffness of the immersion joint are obtained. A quasi-static analysis based on the numerical simulation is presented, in which different water pressures are considered due to the significant variations of the water depth, and the stiffness of the immersion joint under multi-level loads is also studied.