The effect of constant temperature multi-direction forging process on the microstructure and mechanical properties of EW75 magnesium alloy was studied by means of metallographic microscope, scanning electron microscope and tensile testing machine, and the dynamic recrystallization mechanism was analyzed. The results show that dynamic recrystallization occurs in the forged EW75 magnesium alloy sheets at 500 and 470 ℃, while there are a large number of fine granular precipitates observed in the forged EW75 magnesium alloy sheets at 440 and 410 ℃, and no obvious dynamic recrystallization microstructure is observed. The original grain morphology and granular precipitates can be seen in the specimen parallelled to the forging direction, while the deformation streamline can be seen in the specimen perpendicular to the forging direction. Complete dynamic recrystallization takes place in the forged EW75 magnesium alloy sheet at 470 ℃, the average grain size is about 15 μm, and most of the dynamic recrystallization grains in the alloy are large angle grain boundaries. The strength and plasticity of EW75 magnesium alloy sheet after forging treatment are obviously higher than those of solid solution. With the decreasing of forging temperature, both the tensile strength and the specified plastic extension strength of EW75 magnesium alloy sheet show a gradual upward trend, while the elongation after fracture shows first increasing and then decreasing trend. When forging at 470 ℃, the EW75 magnesium alloy sheet has the best plasticity, which is mainly related to the compatible plastic deformation of complete recrystallization and the fact that the larger orientation difference between grains contributes to the grain plane slip.