In　order　to　study　the　relationship　between　debonding　and　temperature　variation　of　concrete-filled　steel　tubular　(CFST)　members,　temperature　field　tests　of　two　concrete-filled　steel　tubular　debonding　members　were　carried　out.　One　was　placed　vertically　and　the　other　one　was　placed　horizontally.　A　finite　element　method　(FEM)　was　used　to　calculate　the　temperature　field　of　debonding　member.　It　was　assumed　that　the　gap　between　steel　tube　and　concrete　was　filled　with　air,　the　inner　boundary　condition　of　the　section　was　considered　to　be　the　contact　boundary　condition　(the　fourth　boundary　condition),　i.　e.　,　the　heat　transferred　from　steel　to　air　in　the　gap　and　then　transferred　from　air　to　concrete.　The　calculating　results　by　FEM　agree　well　with　the　test　results.　Results　show　that　compared　with　steel　tube　of　non-debonding　member,　the　maximum　temperature　increases　and　the　minimum　temperature　decreases　in　steel　tube　of　the　debonding　member　while　it　is　opposite　to　the　temperature　in　core　concrete.　This　situation　is　in　direct　ratio　to　the　gap　when　initial　debonding　gap　is　under　certain　limits.　The　width　of　debonding　gap　changes　with　temperature　variation,　and　widens　with　increase　of　the　diameter　of　tube　and　the　width　of　initial　gap,　but　it　totally　changes　very　small.　Only　when　the　width　is　small　and　the　diameter　of　tube　is　large,　the　gap　may　close　possibly.