The　thermal　deformation　microstructure　of　continuous　extrusion　copper　bus　bar　was　observed　and　analyzed　in　the　temperature　range　from　200°C　to　700°C　and　at　strain　rate　from　0.01s-1　to　10.0s-1　and　at　deformation　amount　from30%　to　90%　on　Gleeble1500　test　machine.　The　experiment　results　show　that　the　higher　the　temperature,　the　lower　the　strain　rate,　the　more　dynamic　recrystallization　occurred.　At　the　same　strain　rate,　the　copper　bus　bar　changes　from　raw　material　of　as-cast　organization　to　recrystallization　grain　gradually　as　the　deformation　temperature　and　deformation　degree　increase,　and　the　recrystallization　grain　size　grows　older　with　the　rise　of　temperature.　At　the　same　deformation　temperature,　the　temperature　of　recrystallization　nucleation　decreases　while　the　strain　rate　increases.　At　low　strain　rate　(0.01~1.0s-1),　the　dynamic　recrystallization　occurred　at　500°C.　While　at　high　strain　rate　(10.0s-1),　the　recrystallization　nucleation　is　advanced　and　it　is　already　completed　at　500°C.　The　Z　parameters　can　be　used　to　express　the　effect　of　deformation　temperature　and　strain　rate　on　the　average　grain　size　D,　and　the　prediction　model　of　the　thermal　deformation　microstructure　is　obtained　as　follows:　LnD=4.822-0.018lnZ.　©　2018　The　Authors,　published　by　EDP　Sciences.