This paper provides one damage identification method for stiffness mutation position of tower structure based on dynamic response information truncation. On the basis of obtaining dynamic response information of tower structure under environment excitation, wavelet transform is adopted for structure damage location identification. When there is mutation point in integral stiffness of tower structure, stiffness mutation will make stiffness change caused by structure damage difficult to identify. Therefore, through stiffness structure analysis, dynamic response information of structure stiffness mutation position is truncated, and the truncated dynamic response information interval is extended, so as to eliminate the influence of Gibbs phenomenon on the boundary of initial dynamic response information interval, so that structure damage identification of extended information interval will be achieved by wavelet transform. Analysis result of examples shows that this method is very effective and reliable for damage identification of stiffness mutation position of tower structure.