In　order　to　evaluate　the　seismic　performance　of　large-rupture-strain　fiber　reinforced　polymer　(LRS　FRP)　confined　non-ductile　reinforced　concrete　(RC)　square　columns　under　earthquake　action,　quasi-static　experiments　were　carried　out　on　seven　FRP-strengthened　RC　square　columns,　including　a　reference　column,　a　carbon　FRP　(CFRP)-strengthened　column,　and　five　LRS　FRP-strengthened　columns.　The　failure　modes,　seismic　performance　parameters,　and　FRP　strain　of　specimens　were　analyzed,　and　the　effects　of　FRP　types　and　fiber　thicknesses　on　the　failure　modes　and　seismic　performance　of　different　specimens　were　studied.　Results　show　that　under　axial　load　and　cyclic　lateral　load,　the　cover　concrete　of　the　reference　column　in　the　plastic　hinge　zone　was　peeled　off　and　crushed,　and　the　longitudinal　bars　were　severely　buckled,　while　the　FRP-strengthened　columns　did　not　experience　concrete　spalling　or　FRP　rupture,　indicating　that　FRP　reinforcement　changes　the　failure　mode　of　non-ductile　column.　Compared　with　the　reference　column,　the　application　of　FRP　significantly　improved　the　ductility　and　energy　dissipation　capacity　of　the　RC　columns,　while　the　increase　in　the　maximum　horizontal　bearing　capacity　was　marginal.　FRP　reinforcement　decreased　the　strain　of　the　longitudinal　bars　and　stirrups,　and　prevented　the　buckling　of　the　longitudinal　bars.　Compared　with　the　CFRP-strengthened　column,　the　large-rupture-strain　advantage　of　LRS　FRP　was　not　obvious.　The　main　reason　was　that　the　axial　load　ratio　was　low　and　the　slenderness　ratio　was　high　in　this　study,　so　that　the　compressive　area　of　the　FRP　confined　concrete　in　the　plastic　hinge　zone　was　small.　Based　on　the　stress-strain　model　of　LRS　FRP-confined　concrete　developed　on　OpenSees　software　platform,　the　experimental　results　were　simulated,　and　the　simulated　curve　agreed　well　with　the　experimental　curve,　which　verified　the　accuracy　and　reliability　of　the　model　in　the　seismic　analysis　of　FRP　reinforced　columns.　Copyright　©2022　Journal　of　Harbin　Institute　of　Technology.All　rights　reserved.