Hot　deformation　behaviors　and　microstructure　evolution　of　304　stainless　steel　were　investigated　by　hot　compressive　deformation　on　a　Gleeble-1500D　simulator　in　the　temperature　range　from　950~1150°C,　under　the　strain　rate　1×10-2s-1,　with　reduction　up　to　50%.　According　to　the　test　results,　the　deformation　activation　energy　of　cast　and　forged　steels　were　calculated.　Through　experiments　and　theoretical　analyses,　the　thermal　activated　deformation　evolution　model　of　the　dynamic　recrystallization　of　cast　and　forged　steels　were　established.　The　results　showed　that　the　dynamic　recrystallization　process　of　forged　steels　can　be　easily　happened,　and　the　dynamic　recrystallization　process　of　cast　steels　were　retarded　significantly,　the　thermal　activated　deformation　evolution　of　dynamic　recrystallization　model＇s　establishment　can　provide　a　reliable　criterion　for　further　numerical　simulation　of　recrystallization.