Elastic　cables　have　the　advantages　of　desirable　seismic　mitigation　effect,　low　cost,　and　convenient　installation,　and　have　been　used　widely　in　low-To-mid-span　bridges.　However,　their　utilization　in　long-span　cable-stayed　bridges　has　been　limited.　To　study　the　effect　of　elastic　cable　on　the　seismic　response　mitigation　of　long-span　cable-stayed　bridges,　an　experimental　model　(half-bridge　model)　with　a　geometric　similarity　ratio　of　1a40　was　established.　Both　the　semifloating　system　and　the　elastic　restraint　system　were　considered,　and　the　seismic　responses　of　the　two　systems　under　earthquake　excitation　were　tested　on　the　shaking　table.　The　results　demonstrated　the　seismic　mitigation　effect　of　the　elastic　restraint　system,　which　is　dependent　on　the　characteristics　of　the　seismic　wave.　The　mechanism　of　the　seismic　response　mitigation　of　the　long-span　cable-stayed　bridge　with　longitudinal　elastic　restraint　was　discussed.　©　2021　American　Society　of　Civil　Engineers.