The high temperature hot compressive deformation behavior of as-cast ZK60-1.0Er magnesium alloy occurring homogenization have been studied by Gleeble-1500D thermal simulator at the strain rate 0.0001s-1,0.001s-1,0.01s-1 and 1.0s-1,the temperature 160℃, 260℃, 320℃ and 420℃. The experimental results show that the competition between work hardening, dynamic recovery and dynamic recrystallization of hot compression deformation of as-cast ZK60-1.0Er magnesium alloy. Constitutive equation of thermocompression of ZK60-1.0Er magnesium alloy was developed by the Zener-Hollomon parameter, theorial stress value which was calculated according to the constitutive equation is in accordance with the actual stress value; Meanwhile according to the material dynamic model, the processing map of this magnesium alloy was obtained, in addition, observing and analyzing metallographic microstructure shows that the processing map contains two instability areas: low temperature high strain rate and high temperature low strain rate. The most optimal hot working range for this kind of alloy: 225~420℃, 0.01~1.0s-1, having one peak efficiency η max = 45%. The existence of rare earth promote dynamic recrystallization nucleation of ZK60-1.0Er magnesium alloy, the average deformation activation energy was 152.5KJ/mol, main mechanisms were dynamic recovery and dynamic recrystallization caused by the grain boundary sliding and lattice self-diffusion.