In　order　to　analyze　the　behavior　of　building　structures　in　a　real　fire,　a　numerical　method　is　proposed,　which　employs　fire　zone　model　to　simulate　the　fire　growing　and　the　temperature　distributions　in　a　firing　room.　Two　computer　programs　are　developed　to　predict　the　thermomechanical　response　of　the　structures,　one　for　thermal　response　analysis,　and　another　for　structural　analysis.　The　structural　analysis　program　contains　a　fiber　beam　element　and　a　layered　shell　element.　These　elements,　validated　against　data　from　experimental　tests,　can　be　used　to　predict　the　response　of　beam/column　and　slabs　in　fire　conditions.　Based　on　these　programs,　a　system　for　analyzing　the　behavior　of　structures　under　fire　is　developed　on　MSC/PATRAN　platform.　The　behavior　of　building　structures　under　fire　can　be　simulated　with　this　system　and　the　results　can　be　used　as　the　reference　for　the　fire　safety　analysis　and　assessment　of　general　building　structures　under　fire.　©　(2011)　Trans　Tech　Publications.