To　study　the　seismic　performance　of　concrete-filled　steel　tubular　composite　columns　with　UHPC　plates.　The　pseudo-static　tests　were　carried　out　on　five　specimens　with　the　longitudinal　distance　of　the　column　limbs　and　thickness　of　the　UHPC　plates　as　test　parameters.　Subsequently,　a　nonlinear　finite　element　model　of　such　com-posite　columns　was　established　based　on　OpenSees,　and　the　calculation　method　of　lateral　bearing　capacity　of　the　specimen　under　compression-bending　load　was　proposed.　The　results　showed　that　the　longitudinal　distance　of　the　column　limbs　significantly　influenced　the　lateral　bearing　capacity　as　well　as　the　initial　stiffness　of　the　specimens.　The　longitudinal　distance　of　column　limbs　was　increased　from　250　mm　to　650　mm,　and　the　lateral　bearing　capacity　as　well　as　the　initial　stiffness　of　the　specimens　were　increased　by　246.0　%　and　488.5　%,　respectively.　The　thickness　of　the　UHPC　plate　was　increased　from　50　mm　to　100　mm,　the　lateral　bearing　capacity　of　the　specimen　was　increased　by　32.2　%,　while　the　cumulative　hysteretic　energy　consumption　was　reduced　by　45.05　%.　Keeping　the　same　axial　pressure　ratio,　the　initial　stresses　in　the　column　limb　steel　tubes　of　the　concrete-filled　steel　tubular　composite　columns　with　UHPC　plates　specimens　were　higher　compared　to　those　of　the　concrete-filled　steel　tubular　composite　columns　with　ordinary　reinforced　concrete　plates　specimens,　resulting　in　poorer　ductility.　The　established　nonlinear　numerical　model　accurately　captured　the　hysteretic　performance　of　the　specimen.　Moreover,　the　proposed　lateral　bearing　capacity　calculation　method　has　high　accuracy　and　can　predict　the　lateral　bearing　capacity　of　such　structures　well.