台灣位處於環太平洋地震帶，結構物受到地震力作用的機會非常大，在地震作用後的結構物是否還擁有和先前一樣的承受能力，是我們所關心的問題。而系統識別就是一個可以從地震力作用後的結構物反應了解結構的動態行為的方法。若結構物在強震作用下發生損壞，即可藉系統識別方法診斷出結構動態特性的改變，進行作損害評估，以判定結構是否損壞、損壞程度及損壞位置，因此正確求得真實結構之動態參數才能準確評估結構之損壞情況，如此才能保障台灣居民的安全。 本論文旨在針對Izuru Tzkewaiki and Mitsuru Nakamura提出的系統識別方法應用在受到真實地震力作用下的建築結構時，其識別效果之探討。並且經由新的推導方式進而推出利用下層的勁度與阻尼識別值即可求出上一層的勁度與阻尼之識別公式，此外再透過數值模擬加以驗證公式在不同地震的狀態下的識別效果。本文也將針對如何更精確的得到識別值加以探討，以達到更精確之識別效果。 Taiwan is a high seismic zone since it is located at the active arc-continent collision region between the Luzon arc of the Philippine Sea plate and the Eurasian plate. The Chi-Chi Earthquake is the largest earthquake occurred in Taiwan during this century. Due to the great damage caused by this earthquake, more and more emphases have been put on the earthquake resistant design of buildings. Dynamic behavior of buildings under earthquakes should be considered in the process of design. In order to realize the dynamic behavior of structural systems subjected to earthquakes, we can determine dynamic models and parameters through system identification techniques. System identified is a method using input and output data we knowed to determine the specific storey stiffness and viscous damping. In this paper, major purpose is to consider the validity and accuracy of identified method proposed by Izuru Takewaki and Mitsuru Nakamura with actual earthquakes records. Besides, in two storey building we can determine stiffness and damping on the second storey using the first storey stiffness, damping and response.