<p>Accurately predicting the amount of sheet springback has practical guiding significance for perfecting the bending forming process and improving the accuracy of products, and the special tension–compression asymmetry of magnesium alloy has gradually become a hot issue in the research of magnesium alloy forming process. In this paper, based on the uniaxial tension and compression stress–strain data of AZ31B magnesium alloy in the rolled annealed state at different temperatures, taking into account the tension–compression asymmetry and neutral layer offset during the sheet bending process, a theoretical model of sheet bending springback with high prediction accuracy has been established. The validity of the results obtained from the theoretical model is jointly verified by the sheet bending springback experiments at room temperature and the sheet bending springback simulations at different temperatures using finite element simulation software. The results show that the established theoretical model of sheet bending springback can reliably predict the springback angle of AZ31B magnesium alloy sheet. The springback angle of AZ31B magnesium alloy sheet at room temperature gradually decreases with increasing sheet thickness and bending angle, and the springback angle of sheets with the same thickness gradually decreases with increasing relative bending radius. The springback angle of AZ31B magnesium alloy sheet gradually decreases with increasing temperature.</p>