台灣地區處於環太平洋地震帶上，地狹人稠，大小地震發生頻 傳，因此近幾年來系統識別越來越受到重視，為了解結構物的動力特 性，有許多專家學者提出各種不同的識別方法，本研究即是以 F.E.Udwadia 於1978 年所提出的識別公式加以做更深入的研究，其 中探討拉普拉斯轉換在解析解與數值解之間的誤差，並導入傅利葉正 弦級數來解決拉普拉斯轉換在參數s 趨近於無窮大時在數值計算上 因電腦有效位數不足所產生的問題，進而提出ㄧ個新的識別公式以利識別。 Taiwan is located at the Circum- Pacific seismic zone. The density of population in this small island is high. Various scales of earthquake occur here frequently. Therefore, system identification has got more and more attention during recent years. In order to find out the dynamic property of structure, there are many professionals and scholars have brought up varied methodology to identify. This research based on the identified equation address by F.E.Udwadia in 1978 and made more deep research. In this research, we discuss the error of Laplace transform between exact solution and numerical solution, and induct Fourier sine series to resolve the arithmetic problem, which due to the defect of effective digit in computer, in the case of parameter ‘s’of Laplace transform approaches to infinity. Further, we derived a new identified equation to identify the dynamic property of structure.