Abstract: To abandon a large number of low signal-to-noise ratio data or normal data, the health monitoring strategy for bridge considering signal-to-noise ratio and vehicle-bridge interaction was proposed. Hence, the computing resources were saved effectively and the targeted monitoring based on theory was realized. The composition of the vibration signal was discussed, and the reasonable and accurate monitoring threshold was determined according to vehicles-bridge interaction dynamics. A timevarying dynamic car group model which included a main uniform parameters and coupling mass was established. The dynamic coupling equations for bridge and car group were established and the analytical expression was given. For example, the health monitoring for a simply supported beam was discussed.The dynamic response under different uniform mass, speed and vibration frequency of the car group was analyzed based on vehicles-bridge interaction theory. The monitoring threshold was determined according to simulated result and measured signal, and the monitoring strategy was realized.Resultsshow that the monitoring strategy is feasible.