Abstract: Regarding multilayer base shake-isolation framework as research object, the influence of SSI effect on baseisolated structure by means of the finite element analysis method is studied. The difference of dynamic characteristic andearthquake response of shake-isolation system which considers SSI effect or not is contrasted. And the influence law ofvarious components of SSI effect to the earthquake response of isolated structure is also discussed. The results indicate that SSI effect has influenced on base isolated structure. In engineering design, isolated structure should not ignore the influenceof SSI effect.