In recent years, overturning accidents involving curved girder bridges with single-column piers have occurred frequently, underscoring the critical engineering significance of conducting anti-overturning analysis and developing effective reinforcement strategies. This study focused on a specific ramp bridge, evaluating its anti-overturning stability by using the bearing failure method and finite element analysis software Midas/Civil. A flexible girder lattice finite element model was established to compare and analyze the anti-overturning stability and dynamic characteristics of the curved girder bridge before and after reinforcement. The results indicate that, prior to reinforcement, the first-order mode of the curved box girder of the ramp bridge exhibited torsional vibration, particularly prone to torsion at pier 4, potentially leading to bearing voids. The minimum anti-overturning stability coefficient was found to be 1.97, failing to meet the required minimum of 2.50, thus indicating insufficient anti-overturning capacity. Post-reinforcement, with the application of additional piers and columns to pier 4, the first-order mode of the curved box girder shifted to longitudinal bending vibration, and the minimum anti-overturning stability coefficient increased to 4.31, demonstrating a significant enhancement in anti-overturning capacity. The efficacy of the reinforcement was further validated through an on-site static load test, which confirmed the positive impact of the implemented measures.