A combined optimization method is proposed to detect the plate structure with multiple damages. Firstly the variety of the first mode can be superposed under the multiple damages. Then the variety rate of the first mode is introduced as the damage signature, and the feature of the superposition is certificated. Finally a combined optimization method is advanced to resolve the detection of the multiple damages of the plate structure. The example of the damage detection to the plate fixed at four sides reveals that the new method is feasible and effective, it not only can finish the damage detection with high precision, but also can simplify the process of the damage detection of the plate structure.
