Abstract: In order to understand the mechanral properties of Lead Rubber Bears， in this paper, nonlinear time history analysis of isolated bridges is conducted. According to the behavior of seismic isolation system for bridges, the nonlinear properties and mutual effect of LRB and bridge structure are considered for the first time. The nonlinear behavior of aseismic bearings and ductile plastic hinges of piers are taken into account by using nonlinear spring element. The results are compared to investigate the isolation performance of different bearings. When nonlinear seismic response analysis is carried out, the isolation effect is discussed.