The Menyuan earthquake in Qinghai, which occurred on January 8, 2022, significantly affected the operational integrity and structural safety of the Liuhuanggou Bridge, a high-speed railway bridge. This event marked the first instance of seismic damage to a high-speed railway bridge in China. The earthquake resulted in a dislocation of the bridge, altering its dynamic characteristics and posing a direct threat to operational safety under severe conditions. To investigate the impact of this seismic event on the bridge, this study constructs a full-scale nonlinear finite element model utilizing ANSYS/LS-DYNA. A comprehensive analysis of the nonlinear seismic time history is conducted based on measured data from the platform, allowing for the inversion of the entire earthquake process. This research emphasizes the longitudinal and transverse displacements of the girder as well as the damage sustained by the bearing components. The finite element simulation results are compared with actual seismic disaster data to elucidate the damage mechanisms affecting the girder components post-earthquake. Furthermore, this paper proposes preventive measures aimed at mitigating earthquake-induced damage to railway simply supported girder bridges. The findings indicate that, despite the absence of collapse, the Liuhuanggou Bridge experienced significant displacements in both transverse and longitudinal directions due to ground motions. Additionally, critical bridge components exhibited severe damage: the bearings sustained complete failure, while the bridge pier pads were damaged to various extents. These observations highlight the necessity for enhanced lateral stiffness in future bridge designs. In summary, the examination of the Liuhuanggou Bridge provides valuable insights into its specific performance and damage during an earthquake. The proposed measures and conclusions drawn from this study serve as a useful reference for subsequent bridge design and seismic resilience efforts, thereby contributing to the enhancement of China's high-speed railway bridges' capacity to withstand seismic disasters and ensuring their safe operation.