Concrete-filled　steel　tube　(CFT)　columns　in　multi-storey　frames　may　be　subjected　to　unequal　end　moments,　especially　during　earthquakes.　The　behavior　of　ultra-high　strength　concrete-filled　steel　tube　columns　(UHSCFT)　with　concrete　strengths　greater　than　100　MPa　subjected　to　unequal　end　moments　has　not　been　studied　thus　far.　In　this　study,　22　UHSCFT　columns　were　designed　and　tested　to　investigate　the　influence　of　the　end　moment　ratio　beta,　eccentricity　ratio　e/D,　and　slenderness　ratio　L/D　on　the　behavior　of　UHSCFT　columns　under　different　end　moments.　The　results　suggested　that　varying　beta　from　1.0　to　0　resulted　in　a　higher　axial　load-bearing　capacity　for　the　UHSCFT　columns　with　e/D　=　0.4,　L/D　=　7.5,　whereas　for　beta　＜=　0,　the　effect　of　the　end　moment　ratio　was　marginal.　Moreover,　the　axial　load-bearing　capacity　generally　decreased　with　increasing　L/D　and/or　e/D　ratios.　Smaller　beta,　smaller　e/D　ratios,　and/or　larger　L/D　ratios　generally　led　to　more　brittle　behavior　in　UHSCFT　columns.　The　second　order　effect　of　UHSCFT　columns　with　equal　end　moments　was　significant,　whereas　those　of　specimens　with　unequal　end　moments　(L/D　＜=　12,　e/D　＜=　0.4)　could　generally　be　neglected.　Current　design　codes,　such　as　EC4,　AISC　360　and　GB　50936,　are　unable　to　well　predict　the　resistance　to　compression　and　bending　of　UHSCFT　columns　under　unequal　end　moments.　It　was　observed　that　the　accuracy　of　GB　50936　would　be　improved　by　assuming　K-a＇　＞=　1.