The dynamic recrystallization behavior, grain orientation and texture formation of magnesium alloy under different deformation conditions (temperature, strain rate and deformation degree) were studied by using electron backscattering diffraction (EBSD) in the thermal compression experiment of AZ31 magnesium alloy. The results show that the greater the deformation temperature, the more adequate the degree of recrystallization and the more uniform the grain structure. The greater the degree of deformation or the smaller the strain rate, the greater the degree of recrystallization. During the hot deformation of magnesium alloys, the deformation temperature is the biggest factor influencing the dynamic recrystallization mechanism. At 300℃, the recrystallized grains of AZ31 magnesium alloy nucleate at the original grain boundary and sub-grain boundary. The recrystallization behavior is mainly formed by the rotation of sub-grain boundary, which shows the typical continuous dynamic recrystallization (CDRX) characteristics. At 400°C, the orientation of the recrystallized grains is deflected during local shear deformation, showing the typical characteristics of rotational dynamic recrystallization (RDRX). During the thermal compression process, {10-12} tensile twins are generated, and the grains re-rotate the basal plane orientation to form a fiber texture with the basal plane perpendicular to the compression direction.