To　enhance　the　seismic　performance　of　buckling-restrained　braces　(BRBs)　and　meet　the　requirements　for　seismic　resilience　under　multi-level　earthquakes,　this　study　proposes　a　novel　double-stage　capacity-adjustable　buckling-restrained　brace　(CABRB).　The　CABRB　features　a　sacrificial　component　and　an　energy-dissipating　BRB　working　in　parallel.　During　small　earthquakes,　the　sacrificial　component　provides　additional　stiffness　and　strength　to　ensure　structural　serviceability.　As　seismic　intensity　increases,　the　sacrificial　component　fails,　helping　to　concentrate　the　seismic　damage　on　the　BRB　component　and　protecting　other　structural　components.　This　study　first　designed　and　conducted　quasi-static　tests　to　evaluate　the　seismic　performance　and　post-earthquake　reparability　of　the　CABRB　equipped　with　various　opening-shaped　sacrificial　plates.　Upon　the　experimental　investigations,　refined　finite　element　models　were　established　to　conduct　parametric　analyses　for　evaluating　the　influences　of　geometric　parameters　of　the　sacrificial　plate　on　the　mechanical　properties　of　the　CABRB.　Additionally,　two-story　braced　frame　numerical　models,　one　equipped　with　BRBs　and　the　other　with　CABRBs,　were　established　and　compared　to　validate　the　feasibility　and　applicability　of　the　CABRBs.　The　results　indicate　that　the　proposed　CABRB,　with　its　unique　double-stage　mechanical　behavior,　not　only　meets　the　multi-level　seismic　performance　requirements,　but　also　exhibits　excellent　post-earthquake　reparability.　This　provides　valuable　insights　and　technical　support　for　the　multi-level　seismic　design　of　civil　structures.　©　2025　Institution　of　Structural　Engineers