Abstract: To manage a large-scale complex structure effectively and reduce damage lost induced by disasters and structural material deterioration, it is nowadays a focus to investigate and develop a large structural health monitoring (SHM) system. Sensor arrangement takes an important role in the SHM system due to its characteristics not only depending on the system performance but also impacting on the management cost. In this paper, the sensor arrangement methods used commonly were introduced firstly, and then a novel sensor arrangement method based on structural vulnerability analysis was proposed. In which, the important factors of members are calculated first, and the redundancy of each members is obtained by the relation of the redundancy and important factor; then the failure modes are searched and determined by the redundancy; afterwards the strain energy of a structure is presented to evaluate the damage demand of a failure mode; consequently the fragility failure path is determined; furthermore, the sensors are arranged based on the fragility failure path. A truss bridge model was validated the proposed method finally. The results show that the proposed method is feasible and effective.