The deformation behavior of squeeze cast ZK60 magnesium alloy was investigated by compressive tests conducted at temperatures of 250-450 ℃ and strain rates of 0.001-10 s-1 with Gleeble-1500D thermal simulator system. The hot deformation behavior of squeeze cast ZK60 magnesium alloy was characterized using processing map developed on the basis of the dynamic materials model. The processing map gives safe "processing windows" in which the processes of dynamic recovery and dynamic recrystallization occur. It reveals that the dynamic recrystallization domain occurs at 375 ℃ and strain rate of 0.001 s-1, and its power dissipation efficiency approximately corresponds to 36%, which should be considered the optimum parameters for hot working of squeeze cast ZK60 magnesium alloy. The variation of the instability parameter ξ(ε) with temperature and strain rate constitutes an instability map, which is used for delineating the region of flow instability. The material exhibits flow instability which should be avoided in mechanical processing.