Abstract: The microstructure and mechanical properties of MB1 magnesium alloy sheet produced by differential speed rolling process under the conditions of different rolling speed ratios (1.2-1.8) and rolling routes were studied.The results show that when the rolling speed ratio increased from 1.2 to 1.6,the grains became refined and twins disappeared gradually,and the tensile strength and elongation all increased.Especially when the rolling speed ratio was 1.6,the alloy had minimum grain size of 20 μm with no twin,its tensile strength and elongation could reach 235 MPa and 23%.However,when the rolling speed ratio increased further,the mechanical properties droped a little.When the routes were changed from A,B,C to D,the grains became refined and twins disappeared gradually,while the strength decreased and elongation increased gradually.