High　temperature　isothermal　compression　experiment　of　3003　aluminum　alloy　was　deformed　at　deformation　temperature　of　300-500　℃,　strain　rate　of　0.01-10.0　s　-1　with　Gleeble-1500　thermal　simulator.　The　results　show　that　the　3003　aluminum　alloy　has　the　positive　strain　rate　sensitivity.　When　the　deformation　temperature　is　lower　than　350　℃,　the　thermal　deformation　mechanism　of　the　alloy　is　mainly　dynamic　recovery.　When　the　strain　rate　exceeds　1.0　s　-1　,　the　thermal　deformation　mechanism　of　the　alloy　is　mainly　discontinuous　dynamic　recrystallization.　A　constitutive　equation　considering　the　effect　of　strain　rate,　strain　and　hot　deformation　temperature　on　the　flow　stress　was　established,and　material　constants　of　the　constitutive　equation　could　be　described　as　four　polynomial　function　of　strain.　The　simulation　results　show　that　the　forecasting　curves　match　well　with　the　experimental　curves.　The　root　mean　square　error　between　the　predicted　flow　stress　values　and　measured　flow　stress　values　is　0.99814　and　average　relative　error　is　5.72%.　The　calculation　accuracy　of　the　established　constitutive　equation　is　good,　which　provides　reference　for　the　thermal　deformation　flow　stress　prediction　of　alloy.　©　2018,　Editorial　Board　of　Journal　of　Plasticity　Engineering.　All　right　reserved.