Reinforced concrete structures are prone to damage during their service lifetime caused by factors such as the effect of overload, ground motions, and other actions. Undetected damage may lead to structural failures. Early detection of damage and timely repairs can prevent catastrophic failure and ensure regular service of structures. As a result, a so-called delimitation wavelet-transform search method, based on the characteristic of multi-resolution of wavelet transform, is presented in this paper for on-line damage identification of reinforced concrete structures. One possible advantage of this method is that the damage temporal and spatial location can be detected rapidly and efficiently. Further research is carried out with numerical simulation of a structure test model to study the storied damage detection and localization of reinforced concrete frame structures under seismic actions. The analyzing result is compared with that observed in a simulated earthquake vibration stand test. Good agreement is obtained and it verifies the effectiveness and validity of the method proposed in this paper.