To ensure the effectiveness and timeliness of the bridge health monitoring system and provide the basis for the maintenance and reinforcement of bridge managers, based on the finite element analysis and sensor monitoring data the structural health monitoring system of the Eight one bridge in Nanchang was taken as the research object and a structural early warning system for multi index parallel warning was proposed. The early warning indices, thresholds and workflow were elaborated and the warning indices, such as cable force, The key section of stress and vertical deformation, fatigue vehicle loads, and the change rates of natural frequencies were particularly calculated and analysed. The results of the research demonstrate that under the current load circumstances, the results of these warning indices are normal and the components can meet the operation requirements.