A novel hydro-mechanical deep drawing for magnesium alloy sheets at gradient temperature is proposed and studied. The novel process is on the basis of the study in sheet metal forming, the properties of magnesium alloy and the forming characteristics of workpiece in deep drawing. It indicates that the deep drawing operation of magnesium alloy sheet should be done in warm condition due to the poor plasticity of magnesium alloy. In addition, the reasonable temperature gradient of the workpiece is necessary in light on the principle of deep drawing. The essence why the limited drawing ratio can be improved with the new process is demonstrated. The reasonable temperature gradient can be obtained by the fluid pressure control during deep drawing operation. Thus the feasibility of the new technology is verified.