To overcome the limitations of low frequency resolution and interference of aliasing distortion of neighboring harmonic in the structure vibration signal analysis using wavelet transform(WT) or wavelet packet transform (WPT) , a new damage feature extraction method is developed based on Ensemble Empirical mode decomposition (EEMD) and WPT. The response signals of the ASCE benchmark structure are processed by using EEMD, the intrinsic mode function (IMF) containing structural damage information are selected.Then, the selected IMF is de composed by orthogonal WPT, and wavelet package energy (WPE) on decomposition frequency bands is calculated to represent the structure condition. The method is used to extract damage feature of the steel frame presented by the American Society of Civil Engineers (ASCE). The main results are summarized as follows: EEMD methods by using the eliminating characteristics of white noise can avoid the occurrence of mode mixing. For different kinds of damage, their WPE distributio ns are different with each other, and for a special damage, the distributions of WPE are different at the different detection nodes, thus it can be used as an ideal target for structural damage characteristics.