Abstract Thermal compression tests of AZ61 magnesium alloy were performed at deformation temperature 423–673 K and strain rates ranged from 0.01 to 10 s−1, and the microstructure was studied. The result shows that dynamic recrystallization (DRX) happened under the warm deformation of AZ61 alloy. One hand, the values of maximum stress decrease when the deformation temperature increases, and the grain size grows up. On the other hand, the critical strain increases with the strain ratio increase. Therefore, temperature and strain ratio can make a great effect on the microstructure and mechanical properties of AZ61 alloy, but temperature is the more important factor.