The development of a real-time monitoring and early warning system and corresponding decision-making procedures has become a high-priority concern for the Taiwanese government in recent years. Studies have indicated that observing water level and scour depth is not sufficient for evaluating bridge safety. Therefore, a high-tech bridge safety monitoring system based on monitoring the vibration behaviour of a bridge is developed in this study and applied to Xibin Bridge. A flood event is recorded and studied to understand the relationship between bridge vibration behaviours and scour. The study results for the monitoring system are verified using in-field vibration measurements and simulations by a numerical model.