In　order　to　study　the　seismic　behavior　of　special-shaped　concrete-filled　steel　tubular　(CFT)　octagon　section　mega-columns　with　different　configurations,　four　1/30-scaled　mega-column　specimens　were　designed　and　tested　under　low-cycle　reversal　loading.　Focus　was　given　to　their　damage　evolution　behavior,　hysteretic　characteristics,　bearing　capacity,　stiffness　degradation,　ductility,　and　energy　dissipation.　Four　different　section　properties　were　considered,　namely,　basic　configuration　with　13　cells,　simplified　configuration　with　5　cells,　section　strengthened　with　corner　angle,　and　section　strengthened　with　corner　circular　steel　tube.　The　research　shows　that　among　the　four　different　cross-section　configurations,　the　one　strengthened　with　corner　circular　steel　tube　shows　the　most　favorable　seismic　performance,　and　the　corner　steel　angle　also　leads　to　satisfactory　behavior.　The　bearing　capacity　of　the　sections　with　5　cells　and　13　cells　differs　significantly,　and　the　ductility　of　the　former　is　better.　In　addition,　the　two　configurations　lead　to　similar　energy　dissipation.　The　average　yielding　drift　ratio　of　specimens　is　1/111,　and　the　drift　ratios　at　failure　point　of　specimens　are　all　larger　than　1/37　indicating　good　ductility.　The　estimated　load　bearing　capacity　using　strip　method　is　shown　to　agree　well　with　the　test　results.　©　2018,　Editorial　Office　of　Journal　of　Building　Structures.　All　right　reserved.