The　3003　aluminum　alloy　was　deformed　by　isothermal　compression　in　the　range　of　deformation　temperature　300-500°C　at　strain　rate　0.01-10.0　s-1　using　Gleeble-1500　thermal　simulator.　The　strain-hardening　rate　could　be　obtained　from　true　stress-true　strain　curves,　and　the　recrystallization　average　grain　size　was　measured　using　the　intercept　method.　The　results　show　that　the　critical　strain　εc　increases　with　parameter　Z　increasing,　the　critical　conditions　for　onset　of　dynamic　recrystallization　(DRX)　is　ε>εc　=　7.28×10-5Z0.1661.　The　average　recrystallization　grain　size　increases　as　deformation　temperature　increases　and　the　strain　rate　decreases,　which　can　be　described　as　lndave=-0.0824lnZ+4.9532.　The　investigated　alloy　is　sensitive　to　positive　strain　rate　under　the　experimental　conditions.　The　true　stress　increases　as　the　deformation　temperature　decreases　and　the　strain　rate　increases.　The　peak　stress　increases　with　the　average　recrystallization　grain　size　decreasing,　which　meets　with　the　law　of　Hall-Petch:　lnσm=-0.9378lndave+6.5232.