Investigate a novel configuration of Tuned Mass Damper-Infinitesimal (TMDI) for achieving longitudinal vibration control of bridges under seismic loads. Firstly, simplify the mechanical model of the TMDI system installed on the bridge and present its power balance equation. Secondly, employ frequency domain analysis to derive the corresponding displacement spectrum of the main structure, followed by utilizing augmented Lagrange optimization method to design the parameters. Finally, elucidate the technical advantages of TMDI systems in controlling bridge vibrations from a power perspective and discuss how bridge period and damping ratio impact TMDI’s vibration damping performance.