Abstract: A new time-domain structural damage identification strategy, improved kinetic energy density-based method, is developed using the measured acceleration signals. The kinetic energy density index is deduced theoretically and an existing method based on this index is introduced. Several faults of this existing method are pointed out and the corresponding reasons are analysed. According to these, an improvement utilized the wavelet packet transform and the correction of datum line techniques is made then. Afterwards, this improved kinetic energy density-based strategy is applied to structural damage detection of a numerical two-span continuous beam model and an experimental three-storey steel frame model. The results verify the effectiveness and performance of this new strategy, show its immunity of the interference of excitation force and noise and demonstrate its adaptability of various structures without complete modal information. Consequently, it is obvious that this new strategy possesses a certain practical engineering value.