Based　on　a　cable-stayed　double-tower　bridge　with　the　main　span　of　680　m,　a　half-bridge　model　was　designed　and　built　with　a　scale　of　1:40.By　using　shaking　table　test,　the　feasibility　of　the　half-bridge　model　to　reflect　the　behavior　of　the　whole-bridge　model　subjected　to　longitudinal　seismic　load　is　studied.　The　boundary　condition　of　the　cable-stayed　bridge　with　double　towers　was　simplified　as　the　half-bridge　model,　and　the　simplified　boundary　condition　was　verified　by　comparing　the　dynamic　characteristics　of　two　models.　The　symmetric　boundary　condition　was　designed　and　the　shaking　table　tests　on　different　half-bridge　model　structural　systems　subjected　to　longitudinal　seismic　loading　were　conducted.　The　efficacy　of　viscous　dampers　with　longitudinal　settings　to　mitigate　the　seismic　response　of　cable-stayed　bridge　was　investigated.　It　is　found　that　given　the　uniform　excitation　ground　motion　at　different　PGA　values,　the　half-bridge　model　yields　similar　seismic　responses　as　the　full-bridge　models.　In　addition,　the　viscous　dampers　are　effective　in　suppressing　the　seismic　response　of　the　cable-stayed　bridge　with　floating　system.　©　2020,　Editorial　Office　of　China　Civil　Engineering　Journal.　All　right　reserved.