Bolted-flange　connections　for　CFST　columns　for　prefabricated　composite　structures　were　investigated　to　be　used　in　prefabricated　multi-story　or　high-rise　buildings.　Six　column　splice　connection　tests　were　conducted　subjected　to　combined　actions　of　bending　and　shear　forces,　changing　with　the　stiffener　numbers　and　flange　thicknesses.　A　finite　element　model　was　built　to　supplement　the　results,　e.　g.　the　joint　stiffness　and　strength,　the　bolt　tension　variation,　the　contact　force　between　the　flanges,　the　yield　mechanics　and　the　failure　modes.　Based　on　the　results,　the　joint　moment　resistance　and　stiffness　would　obviously　increase　after　adding　the　stiffeners.　Design　recommendations　for　the　connection　construction　were　proposed.　Formulas　to　calculate　the　moment　resistance　of　the　joint　were　deduced　according　to　the　yield　of　flanges　and　bolts　and　validated　against　test　and　finite　element　simulation　results.