Abstract: The effects of differential speed ratio on the microstrueture and the texture of AZ31 magnesium alloy sheets processed by differential speed rolling (DSR) were investigated by optical microscopy and X-ray diffraction analysis. The results show that differential speed ratio has a significant effect on the grain morphology but a little influence on the grain size. As the differential speed ratio increases to 2.800, lots of long-strip grains are found. The intensity of 0002 basal textures is much higher on the side of fast rolling than on the side of slow rolling and the distributions of 0002 orientations are different between the two surfaces of the sheet. Differential speed ratio has also a great influence on the strength of basal textures and when the differential speed ratio increases, the intensity of (0002) basal textures increases firstly and then reduces. This special texture change could be attributed to shear deformation introduced throughout the thickness during the differential speed rolling process.