Supercritical　water　(SCW)　fluidized　bed　is　a　new　and　promising　reactor　for　gasification　of　wet　biomass.　In　this　paper,　the　particle　distribution　and　fluid　hydrodynamic　characteristics　in　SCW　fluidized　bed　were　studied　comprehensively　by　the　discrete　element　method　(DEM).　The　results　from　DEM　simulation　show　that　there　exists　a　non-bubbling　fluidization　when　superficial　velocity　is　in　the　range　of　minimum　fluidization　velocity　and　minimum　bubbling　velocity　although　the　particles　are　categorized　as　Geldart　B.　Particle　circulation,　including　internal　circulation　and　gross　circulation　are　responsible　for　solids　mixing　in　SCW　fluidized　bed.　Particle　circulation　in　SCW　fluidized　bed　is　not　only　induced　by　bubble　motion,　but　also　influenced　by　the　vortices　in　bubbles.　Other　characteristics　such　as　voidage　distribution,　particle　and　fluid　velocity,　granular　temperature,　and　particle　Reynolds　number　in　SCW　fluidized　bed,　are　also　discussed.　(C)　2014　Elsevier　Ltd.　All　rights　reserved.