Calculation　methods　for　the　stability　factor　of　CFST　columns　from　foreign　design　criteria　(including　the　American　institute　of　steel　construction　AISC-LRFD　and　the　European　design　of　composite　steel　and　concrete　structures　EC4)　are　introduced.　Either　for　CFST　single　tube　column　or　CFST　laced　column,　the　method,　in　which　the　relative　slenderness　ratio　of　the　column　is　calculated　first　and　stability　factor　is　then　obtained　from　the　corresponding　formula,　can　be　applicable.　Following　this　idea,　a　unified　method　for　calculating　the　stability　factor　of　CFST　columns　is　put　forward　on　the　base　of　analysis　of　the　calculation　methods　of　domestic　and　international　design　criteria.　Test　verifications　of　the　new　calculation　method　on　CFST　single　tube　columns,　dumbbell　shaped　columns　and　laced　columns　are　presented,　and　the　results　indicated　that　the　calculated　values　of　stability　factors　using　this　new　method　agree　well　with　the　test　values.