The Mg-9Al-3Zn-1Mn-6Ca alloy billets were produced by spraying deposition method（the Osprey process）.The microstructure evolution between recrystallization and superplasticity of the deposed billets prepared was observed during pre-deformation and compression deformation.The results show that the superplastic compression deformation can be observed at 350 ℃ and 0.002s-1

and the elongation of outer edge of circumferential reaches up to 103.96%.Superplastic behavior

in which the hardening rate and the dynamic softening rate realize dynamical equilibrium

is accompanied with the occurrence of dynamic recrystallization at 350 ℃

and the strain rate is the key to the superplastic compression deformation in hot-extruded magnesium alloys modified by high-Ca alloying.