Finite　element　models　established　by　ANSYS　software　were　used　for　parameter　studies　of　CFST　laced　columns　axially　loaded.　Calculation　results　indicate　that　besides　steel　type　and　concrete　strength,　the　influence　of　steel　ratio　of　CFST　longitudinal　members　on　stability　factor　should　be　taken　into　account.　With　the　same　equivalent　slenderness　ratio　of　the　CFST　braced　column,　the　greater　the　steel　ration　of　the　longitudinal　members　is,　the　smaller　the　stability　factor　is.　Taking　the　domestic　design　criteria　of　steel　structures　as　reference,　formula　to　calculate　the　material　modification　factor　γ　of　CFST　laced　columns　stability　was　developed　based　on　the　theoretical　derivation　and　numerical　analysis　of　engineering　examples.　The　relevant　table　is　provided　for　the　convenience　of　use.　Analysis　results　of　examples　indicate　that　the　calculated　values　of　material　modification　factor　γ　by　the　formula　agree　well　with　the　finite　element　calculation　values.　The　calculation　method　of　γ　in　this　paper　is　adopted　to　engineering　application　and　it　can　provide　reference　for　the　revision　of　design　criteria.