A　low　tower　cable-stayed　bridge　with　a　span　of　30m+60m+120m+60m+　30m　had　been　built　before　Guidelines　for　Seismic　Design　of　Highway　Bridge　was　promulgated.　Because　of　its　importance　and　specificity,　it　is　necessary　to　do　research　on　seismic　performance　of　the　bridge.　Based　on　three-dimensional　finite　element　model,　it　is　found　that　the　bearing　deformation　across　the　bridge　is　very　big,　and　it　might　be　destroyed　if　earthquake　happened.　In　this　article,　a　new　damper　(Metal　Alloy　Brace)　is　used　to　achieve　seismic　strengthening.　Under　frequently　occurred　earthquake　excitation,　MAB　will　supply　a　small　stiffness,　but　its　hysteretic　curve　is　plump,　so　the　structural　deformation　is　reduced.　Under　rare　earthquake　excitation,　MAB　can　supply　so　big　stiffness　that　the　structural　deformation　is　limited,　and　the　damper　will　also　dissipate　much　energy.　Through　comparing,　it　is　found　that　MAB　is　better　that　caging　device.　And　the　damper　has　no　problem　with　leakage　and　metamorphism.　So,　MAB　has　a　good　prospect　in　seismic　strengthening.　©　2011　ASCE.