Tower cranes belong to the high-risk special equipment due to their own structural characteristics and the attributes of high-altitude operation, and they are prone to heavy casualties. When tower cranes have minor damage, timely detection and maintenance are the basis and premise to avoid the risk of accidents. Based on the engineering background of QTZ100 tower crane on a new project site of a university in Shanghai, the damage compliance curvature was taken as the damage index. The finite element calculation model was built to analyze the variation of structural stress and modal parameters under various minor damage conditions, and compared with the analysis results using the change rate of vibration mode as the damage index. Results show that the damage compliance curvature curve produces obvious mutation at the damage point, through which the location and degree of minor damage can be identified with good anti-noise performance.