The purpose of this work is to experimentally investigate the effect of annealing treatment on the formability and springback at room temperature for magnesium alloy AZ31 sheets, which were produced by rolling through reversible warm mill after twin roll strip casting. Microstructure evolutions were investigated using OM after annealing at temperature raging from 350°C to 450°C. Tensile tests at room temperature were performed to show the influence of annealing treatment on mechanical properties. In order to evaluate the formability in stamping processes, the Erichsen cupping tests were carried out and the Erichsen number were measured. As for springback, the V shaped air bending tests were achieved and the angle changes after springback were collected. The experimental results showed that Erichsen numbers increased by the annealing treatment, while springback angle decreased.