Falling beam is one of the most common seismic damages for high-speed railway bridges, and it influences the running safety of trains. To prevent falling beam and then ensure the running safety of trains, a new anti-drop-beam device is developed for high-speed railway bridge in high intensity seismic regions in this paper. Firstly, the formulas are derived through the theoretical analysis to calculate mechanical parameters and force-displacement constitutive relation of device. Secondly, two groups of experiments are carried out to study mechanical performance of device and validated derived formulas. Finally, the finite element model of a high-speed railway continuous bridge is established to study seismic performance of device. The results show that the derived formulas can accurately calculate mechanical parameters and force-displacement constitutive relation of device. The energy dissipation capacity and low-cycle fatigue performance of device are good. The device can effectively limit the beam end displacement and well dissipate seismic energy under earthquakes, and it can be applied in engineering practice.