According to the accurate and practical damage assessment method， the damage degree of the seismic-damaged structure can be quantified in real time， and the structural repair and reinforcement can be effectively guided. In view of the actual engineering conditions and the shortcomings of the existing damage assessment or identification method in terms of accuracy and feasibility，a generalized damage assessment method is proposed based on the traditional elasto-plastic energy dissipation difference ratio method， which eliminates the influence of mass by shear ratio. The dynamic damage assessment of structure can be realized only by seismic signal and structural dynamic response. On this basis， a method is proposed to deduce the ideal elastic response of the structure by using the foreshock signal and Kalman filter identification technology， and to realize the real-time damage assessment of the whole structure and floors by using the main shock signal. Taking two reinforced concrete frame structure as analysis examples， the results show that the proposed method can accurately indicate the dynamic evolution process of the overall damage and the distribution of weak stories. Compared with the traditional elasto-plastic energy dissipation difference ratio method and the damage assessment method based on frequency change rate， this method has good engineering practicability and can provide effective guidance for the rapid damage assessment of actual earthquake damaged structures.