The stress distribution in the AZ80bar extrusion pipe was simulated by the DEFORM-3Dat different speeds（10mm/s、50mm/s、100mm/s）under four temperatures（150 ℃、200 ℃、250 ℃、300 ℃）

respectively.The results show that stress in the AZ80alloy pipe is increased with decreasing in temperature and increasing in the speed.The simulated result also reveal that magnesium alloy pipe can be formed with high speed（100mm/s）under low temperature（150℃）

and device stress is less than the design limits（400MPa）during the whole extruding process.At the same conditions

magnesium alloy tube was extruded successfully with self-made extrusion device.