Supercritical　water　(SCW)　fluidized　bed　is　a　new　reactor　concept　for　gasification　of　wet　biomass.　In　this　paper,　the　Eulerian　two-fluid　model　based　on　Kinetic　Theory　of　Granular　Flow　in　fluidized　bed　was　established,　and　the　physical　model　of　movement　of　single　bubble　up　the　wall　was　adopted.　The　comparison　studies　of　particle　distribution,　temperature　distribution　and　transient　heat　transfer　characteristics　between　the　SCW　and　gas　solid　fluidized　bed　were　carried　out.　The　results　show　that　the　bubble　diameter　and　rise　velocity　in　SCW　fluidized　bed　are　smaller　than　those　in　gas　solid　fluidized　bed.　With　the　increasing　solid　volume　fraction　near　the　wall,　the　bed-to-wall　heat　transfer　coefficient　decreases　in　SCW　fluidized　bed,　while　it　increases　in　gas　solid　fluidized　bed.　What　is　more,　the　bed-to-wall　heat　transfer　coefficient　is　sensitive　to　superficial　velocity　where　the　solid　volume　fraction　is　low,　which　is　different　from　that　in　gas　solid　fluidized　bed.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.