Based　on　the　Program　NFEACFST　(the　details　of　the　Program　is　listed　in　Yang　2003),　influences　of　parameters　on　residual　load　bearing　capacities　(Ncr)　after　exposure　to　the　ISO-834　standard　fire　are　analyzed.　The　parameters　include　temperature　ascending　time　ratio,　fire　load　ratio,　cross-sectional　dimensions,　steel　ratio,　material　strength　and　slenderness　ratio,　etc.　It　is　found　that　time　ratio,　fire　load　ratio,　cross-sectional　dimensions　and　slenderness　ratio　are　important,　whilst　the　other　parameters　may　be　ignored,　According　to　this　conclusion,　a　simplified　calculation　formula　of　Ncr　after　exposure　to　the　ISO-834　standard　fire　is　then　provided.　Moreover,　The　formula　is　confirmed　by　the　calculated　results　using　the　Program　NFEACFST.　The　research　in　this　paper　can　provide　some　useful　references　for　application　of　this　kind　of　columns　in　engineering　practice.