Aiming at the disadvantage that conventional structuring element for the mathematical morphological can’t adjust its height adaptively,the quantum theory is employed to propose compound quantum-inspired structuring element for erosion（ CQSEE）,which is used for extracting fault information in vibration signal from mechanical transmission system. Since CQSEE utilizes quantum theory to depict noise and fault information,it maturely considers different characteristics of noise and fault information during computational process,which realizes the goal of adjusting height of structuring element dynamically. Then CQSEE is applied to analyze the fault signal of rolling element bearing. The result reveals that CQSSE improves the morphological ability of erosion operator.