This　paper　investigated　the　seismic　behavior　of　high-strength　concrete-filled　square　steel　tube　columns　reinforced　with　ultrahigh-strength　reinforcing　bars.　Three　full-scale　specimens　with　different　amounts　of　ultrahigh-strength　longitudinal　reinforcing　bars　under　a　high　axial　load　ratio　and　cyclic　lateral　load　were　tested.　The　test　results　demonstrate　that　the　existence　of　ultrahigh-strength　longitudinal　reinforcing　bars　had　a　significant　influence　on　the　seismic　behavior　of　high-strength　concrete-filled　steel　tube　columns.　Compared　with　conventional　concrete-filled　steel　tube　(CFT)　columns,　the　deformation　capacity,　bearing　capacity　and　cumulative　energy　dissipation　of　these　innovative　CFT　columns　are　greatly　improved,　and　the　cumulative　damage　and　plastic　deformation　of　the　specimens　decreased　with　the　introduction　of　steel　bars.　A　calculation　model　based　on　AISC360-16　using　the　superposition　method　was　proposed　and　verified　to　evaluate　the　compressive-flexural　strength　of　the　specimen.