The hot compression simulation of an experimental Mg-Zn-Nd alloy at different temperatures is studied by the Gleebe-1500 equipment. The deformation is performed with the strain rates 0.1s(-1), O.Ols(-1) and 0.002s(-1). The plastic deformation behavior is analyzed at different temperatures and the deformation activation energy is calculated. The microstructures of experimental alloy during the deformation process are observed. The results show that the working hardening, dynamic recovery and dynamic recrystallization (DRX) operate under different temperatures and strain rate. The DRX starts when the temperature is over 473K and the DRX grain size after hot deformation is only 5 similar to 10 mu m. So the refined grains improve both the tensile strength and elongation of alloys at room temperature. The precipitate phase Mg(12)Nd impede the movement of dislocations, it benefit to the mechanical properties and grain refining of magnesium alloy.