Influences of processing parameters on microstructure of extruded ZK60 magnesium alloy tube were investigated. The results show that the suitable extruding parameters for ZK60 magnesium alloy tube are presented as follows: semi-angle of cone-shaped die of 70°

billet temperature of 300～360 ℃

and mold pre-heating temperature of 270～330 ℃

extrusion speed of 1.5 mm/s and animal fat lubricant. The grain size can be fined in the extruded tube with increasing in extrusion speed and decreasing in extrusion temperature

however

the extruded force is increased. At a given forming temperature

the extruded force in isothermal forming is decreased by 20% than that of non-isothermal forming. With the extrusion temperature of 300～360 ℃

the dynamic re-crystallization occurs completely with fine and uniformly distributed microstructure. The grain size is fined by 40% of the original grain.