The　earthquake　damage　has　shown　that　the　axchitecture　structure　is　mainly　affected　by　horizontal　earthquakes　action.　A　nonlinear　time　history　analysis　of　a　base-isolated　masonry　structure　with　two-story　frame　structure　on　bottom　modeled　as　a　two-dimensional　finite　element　model　is　made.　On　the　basis　of　the　model,　two　components　of　the　real　recorded　earthquake　ground　motions　(two　horizontal　components)　are　adopted.　The　results　show　that　the　horizontal　seismic　responses　of　the　base-isolated　building　are　remarkably　less　than　those　of　the　fixed　building,　especially　in　the　transition　story　with　abrupt　change　of　stiffness.