Isothermal　compression　tests　of　a　new　type　Al-Zn-Mg-Er-Zr　alloy　are　carried　out　on　a　Gleeble-3800　thermal　simulator　at　temperatures　varying　from　573　to　733　K　and　strain　rates　ranging　from　0.001　to　10　s(-1).　Processing　maps　have　been　constructed　to　study　on　hot　workability　characteristics　of　the　alloy.　The　results　show　that　the　stable　and　unstable　regions　in　the　processing　maps　of　Al-Kn-Mg-Er-Zr　alloy　should　be　identified　based　on　the　comprehensive　consideration　of　the　strain　rate　sensitivity　m,　power　dissipation　efficiency　eta　and　instability　criterion　xi(epsilon)　.　The　processing　maps　exhibit　two　regions　with　high　efficiency　of　power　dissipation:　one　is　at　temperature　of　620-680　K　and　strain　rate　of　0.001-0.003　s(-1);　another　is　at　temperature　of　680-733　K　and　strain　rate　of　0.001-0.1　s(-1).　The　highest　h　value　occurs　at　about　653　K/0.001　s(-1)　and　the　peak　h　values　are　all　above　37%.　According　to　the　microstructure　observation,　the　flow　instability　is　manifested　as　adiabatic　shear　bands　and　flow　localization,　while　the　microstructures　characteristics　in　the　＂safe＂　domains　mainly　exhibit　dynamic　recovery.　The　presence　of　coherent　L1(2)-structured　Al-3(　Er,　Zr)　particles　effectively　pin　the　dislocation　movement　and　the　subgrain　boundary　slide　so　as　to　restrain　the　occurrence　of　dynamic　recrystallization　behavior,　and　the　dominant　softening　mechanism　is　dynamic　recovery　during　isothermal　compression.　(C)　2016　Elsevier　B.V.　All　rights　reserved.