Based　on　the　theory　of　processing　map　proposed　by　PRASAD,　the　power　dissipation　maps,　the　hot　deformation　instability　maps　and　the　hot　processing　maps　of　1235　Al　alloys　treated　by　different　methods　of　purification　were　built,　and　the　effects　of　purification　and　deformation　conditions　at　elevated-temperature　on　hot　workability　of　1235　Al　alloy　were　analyzed.　At　the　same　time　the　optimum　processing　region　and　flow　instability　region　were　determined.　The　results　show　that　the　hot　processing　map　of　1235　Al　alloy　has　two　instability　zones　in　the　temperature　range　of　300-500°C　and　in　the　strain　rate　ranging　from　0.01s　-1　to　10.0s　-1　up　to　a　true　strain　of　0.7,　that　is,　one　zone　lying　in　the　range　of　lower　temperature　and　higher　strain　rate,　the　other　zone　in　the　range　of　higher　temperature　and　mid　strain　rate.　The　purification　effect　has　significant　impact　on　hot　workability　of　the　alloy.　It　is　found　that　the　optimum　processing　region　of　1235　Al　alloy　treated　by　high-efficient　purification　treatment　is　present　in　the　range　of　higher　temperature　and　lower　strain　rate　zone,　and　its　power　dissipation　efficiency　is　about　46%;　while　the　optimum　processing　region　of　1235　Al　alloys　treated　by　conventional　refining　treatment　is　present　in　the　range　of　mid-temperature　and　lower　strain　rate　zone　or　in　the　range　of　higher　temperature　and　strain　rate　zone,　and　its　power　dissipation　efficiency　is　about　23-29%.　The　results　of　observation　of　the　deformation　microstructure　of　1235　Al　alloy　are　in　accordance　with　that　of　the　hot　processing　maps　of　the　alloy,　thus　showing　that　the　calculation　results　of　the　hot　processing　maps　are　reliable.