Double　deck　viaducts　relied　on　ductility　design　are　vulnerable　to　earthquake-induced　damage.　To　controlling　the　seismic　damage,　a　new　double　deck　bridge　with　the　low　piers　designed　as　the　rocking　structure　is　proposed.　The　seismic　analysis　model　of　the　structure　is　derived　by　using　the　Lagrange　method　and　momentum　conservation　law.　The　seismic　behavior　is　studied　by　comparing　with　monolithic　reinforced　concrete　double　deck　bridge.　The　result　shows　that　the　rocking　of　the　lower　floor　structure　can　significantly　reduce　the　deformation　of　upper　structure　as　well　as　avoid　plastic　damage.　©　2020　IEEE.