In　order　to　reveal　the　influence　and　mechanism　of　structure　size　on　seismic　performance　of　reinforced　concrete　(RC)　shear　walls,　six　RC　shear　walls　of　different　sizes　with　the　maximum　length　of　1.　8　m　and　the　shear　span　ratio　of　1.　17　were　designed.　The　seismic　performance　of　shear　walls　under　constant　axial　load　and　cyclic　horizontal　loading　was　studied.　The　effects　of　the　structure　size　and　the　horizontal　reinforcement　ratios　(0.　25%　and　0.　5%)　on　the　seismic　performance　of　RC　shear　walls　were　analyzed,　including　failure　modes,　hysteretic　properties,　deformation　capacity,　energy　dissipation　and　stiffness　degradation.　The　test　results　show　that　the　six　shear　walls　with　horizontal　reinforcement　ratios　of　0.　25%　and　0.　5%　fail　in　brittle　shear　and　compression-shear,　respectively,　and　with　the　increase　of　specimen　size(the　length　of　shear　wall　increases　from　600　mm　to　1　800　mm),　the　deformation　capacity　and　energy　dissipation　capacity　decrease　obviously.　When　the　length　of　shear　wall　increases　from　600　mm　to　1　800　mm,　the　ductility　coefficient　decreases　by　38%,　the　softening　rate　increases　by　142%,　and　the　energy　dissipation　coefficient　decreases　by　38%;　the　nominal　cracking,　yield　and　shear　strength　of　the　shear　wall　decrease　significantly　with　the　increase　of　the　length.　When　the　length　of　shear　wall　with　horizontal　reinforcement　ratios　of　0.　25%　and　0.　5%　increased　from　600　mm　to　1　800　mm,　the　nominal　cracking,　yield　and　shear　strength　decrease　by　57%　and　64%,　18%　and　26%,　19%　and　24%,　respectively,　indicating　that　the　size　effect　is　significant;　with　the　increase　of　horizontal　reinforcement　ratio(increases　from　0.　25%　to　0.　5%),　the　shear　capacity,　deformation　capacity,　nominal　cracking,　yield　and　shear　strength　of　the　shear　wall　are　all　enhanced,　but　the　size　effect　is　suppressed　obviously.　In　addition,　the　experimental　results　confirm　the　accuracy　and　rationality　of　size　effect　law　proposed　in　previous　study　of　our　lab,　which　can　be　used　to　calculate　the　nominal　shear　strength　of　RC　shear　walls.　©　2024　Science　Press.　All　rights　reserved.