Magnesium sheets prepared by traditional plastic processing technologies always exhibit undesirable mechanical properties, which is inefficient and costly for commercial application. High strain rate rolling (HSRR) was operated on AZ31 magnesium alloy. The microstructure and mechanical properties of the HSRRed sheets pre -treated in two different ways were investigated. The results indicated that HSRR was an effective method to produce magnesium alloy sheets characteristic of fine grains and high comprehensive mechanical properties. The pre -strain plus homogenization pre -treatment could significantly improve the microstructural homogeneity of the high strain rate rolled sheet, in which the fine grains were distributed very homogeneously and the average grain size was 2.3 μm. The ductility of the sheet was enhanced due to the improved microstructural homogeneity, and the elongation at room temperature was up to 28%.