3003　Al　alloy　samples　with　various　metallurgical　qualities　were　obtained　by　various　melt-treatment　methods　and　were　deformed　by　isothermal　compression　in　the　deformation　temperature　range　of　300°C　to　500°C　at　strain　rates　between　0.0l　and　10.0　s　-1　with　a　Gleeble-1500　thermal　simulator.　The　results　show　that　there　is　a　close　relationship　between　melt-treatment　and　subsequent　thermal　deformation.　The　hot　deformation　activation　energy　(Q)　bears　a　linear　relationship　with　the　inclusion　content　(H)　of　3003　Al　alloy　prepared　by　various　melt-treatment　methods,　that　is　Q　=　35.62　H　+　171.58.　The　activation　energy　of　the　3003　Al　alloy　prepared　by　the　highly　efficient　melt-treatment　is　the　lowest　(174.62　kJ•mol　-1),　which　is　beneficial　to　the　material　hot　plastic　deformation.　The　critical　strain　of　the　3003　Al　alloy　prepared　by　various　melt-treatment　methods　is　investigated　through　the　work　hardening　rate.　Finally,　the　critical　conditions　of　the　investigated　alloy　were　determined　to　predict　the　occurrence　of　dynamic　recrystallization.　©　2012　The　Korean　Institute　of　Metals　and　Materials　and　Springer　Netherlands.