Abstract: Magnesium-based alloys, as "third-generation biomedical materials", have attracted the attention of many scholars for their excellent biocompatibility and degradability. In the context of traditional medical bone implant devices, which are difficult to degrade, it shows its unique potential. However, it is difficult to predict its performance in clinical applications due to the unknown rate of corrosion damage and degradation under the stress and corrosive effects of the human body fluid environment after implantation. Therefore, in order to prevent premature fracture failure due to excessive degradation, a numerical model applied to the prediction of corrosion performance of metals was developed in this study to investigate the in vitro corrosion behaviour of AZ31B magnesium alloy splints, and the stress-corrosion susceptibility of the splints was assessed by in vitro corrosion tests, and several sets of tests were conducted to obtain data to calibrate the model parameters. The results show that the established model can accurately predict the corrosion damage, degradation rate, and mechanical property damage of implants under different stress loads. Therefore, the stress corrosion model has the potential as a numerical simulation tool to accurately predict corrosion behaviour while optimising the degradation rate of implants. In addition, the procedures and methods of the proposed model are applicable to the stress corrosion prediction of splints with different alloy compositions and mul- tiple application scenarios, which can help to achieve an accurate regulation of the degradation rate of implant materials.