Abstract: The combined seismic isolation bearing is composed of a sliding friction bearing and an elastomeric bearing. The bearing system offers a substantial vertical support capacity, various post-yield stiffness choices, and the ability to separate the bridge’s vertical support system from the horizontal support system. To investigate the seismic performance of the combined seismic isolation bearing system, by way of example of a continuous beam bridge with each continuous unit of (4 × 40) m spans, the OpenSees software was used to model with the conventional spherical steel bearing, full sliding friction bearing and combined seismic isolation bearing support systems to obtain the longitudinal seismic response of the bridges, respectively. The influence of seismic parameters such as sliding friction coefficient and shear stiffness on the seismic performance of the combined seismic isolation bearing was discussed. The results demonstrated that the combined seismic isolation bearing exhibits excellent seismic performance and self-centering ability. The seismic performance of the combined isolation bearing will be affected by the sliding friction coefficient and shear stiffness. By selecting appropriate seismic parameters, the maximum displacement demand of bearings, the residual displacement of bearings, and the seismic response of the piers can be effectively controlled.