This study investigated the effect of the seismic mitigation measure of a type of elastomeric bearing system with the sliding plate and seismic dowel. Firstly, combining the idea of the performance-based seismic and seismic guidelines of China, three performance metrics of the seismic dowel under different earthquake levels (normal service condition, frequent-occurred earthquake and rare-occurred earthquake) were proposed in terms of the seismic force of column or the displacement of the girder. Then, a detailed design methodology of seismic dowel was proposed to establish the hysteretic model and the simplified calculation formula. Finally, a medium-span beam bridge was taken as an example, six suitable earthquake records were chosen and the dynamic mode was established to apply the nonlinear time history analysis using OpenSees. The analytical results show that the proposed seismic mitigation measure can effectively reduce the displacement of the girder and the residue displacement under frequent-occurred earthquake, and it also can decrease the internal force of column dramatically.