To　study　the　shear　behavior　of　RC-encased　CFST　columns　with　interfacially　welded　annular　rebars,　the　transverse　shear　static　test　and　numerical　simulation　of　six　composite　column　specimens　were　carried　out　with　the　spacing　and　the　diameter　of　annular　rebars　as　research　parameters,　and　the　influence　laws　of　various　parameters　on　failure　process,　failure　mode,　load-midspan　deflection　curve　and　shear　bearing　capacity　of　the　specimens　were　investigated.　The　results　show　that　the　failure　modes　of　composite　columns　with　different　arrangements　of　interface　annular　rebars　were　basically　the　same,　and　all　of　them　exhibited　oblique　pressure　failure.　The　stress　process　of　the　specimen　can　be　divided　into　four　stages:　elastic　stage,　elasto-plastic　stage,　hardening　stage　and　failure　stage.　With　the　decrease　of　the　spacing　of　interface　annular　rebars,　the　shear　bearing　capacity　of　the　specimen　was　significantly　improved,　with　the　maximum　increase　of　22%.　Increasing　the　diameter　of　interface　annular　rebars　can　improve　the　shear　capacity　of　the　specimen,　but　the　effect　was　limited,　and　the　maximum　increase　was　only　6.1%.　The　validity　of　the　finite　element　model　was　verified　by　the　experimental　data,　and　the　stress　states　of　the　finite　element　model　at　different　stages　were　further　analyzed,　and　the　shear　mechanism　of　this　kind　of　composite　column　was　clarified.　©　2024　Tsinghua　University.　All　rights　reserved.