The　collapses　of　building　structures　in　fire　have　occurred　several　times　during　the　last　two　decades.　To　save　lives　from　the　collapsed　building,　a　reasonable　method　is　to　predict　the　collapse　of　the　structure　in　advance,　for　being　able　to　evacuate　the　persons　on　site,　such　as　fire-fighters,　before　the　deadly　collapse　will　occur.　Therefore,　in　fire　condition,　the　early-warning　of　structural　collapse　or　member　failure　based　on　accurate　on-site　data　collection　and　refined　failure　state　determination　is　becoming　a　key　issue　in　the　fire　research　field.　A　parameter　measured　easily　-　the　temperature　-　is　taken　as　the　indicator　of　the　fire-induced　failure,　and　an　investigation　on　the　refined　critical　temperatures　of　the　concrete　filled　steel　tubular　(CFST)　columns　will　be　described　in　this　paper.　A　series　of　fire　resistance　tests　on　CFST　columns　were　conducted　and　are　reported　in　this　paper,　and　the　influence　of　different　test　parameters,　including　column　load　ratio　(0.3,　0.4　and　0.6),　section　type　(circular　and　square　sections)　and　fire　scenario　(fire　exposure　on　two　surfaces　and　all　around　the　column),　on　the　critical　temperatures　of　CFST　columns　are　discussed.　Based　on　the　test　data　and　validated　finite　element　analysis　(FEA)　models,　refined　critical　temperatures　(RCTs)　for　CFST　columns　were　defined　and　are　discussed.　Compared　with　the　traditional　critical　temperature,　the　RCTs　clearly　defined　the　positions　and　values　of　critical　temperature　points,　which　makes　it　applicable　to　be　used　as　the　early-warning　of　fire-induced　failure　of　CFST　columns.