近年來，非線性時間數列分析是一個快速發展的課題，其中最為人所矚目 的是門檻模式。從過去許多文獻得知，一個簡單門檻模式對於某些型態時 間數列的描述，如結構性改變的行為趨勢，比一般線性ARMA模式更能解釋 實際情況。在本篇論文中，我們將討論有關門檻模式及結構性改變分析的 問題。對於模式的建立，我們提出一個轉型期的觀念，替代傳統尋求一個 轉捩點的方法，進而提出一個結構性改變ARIMA模式有效建立的程序。最 後，我們以台灣出生率當作應用分析的範例，並且利用建立的結構性改變 ARIMA模式，及其他傳統門檻TAR模式，傳統線性分析方法等進行預測分析 及比較。 / Non-linear time series analysis is a rapidly developing subject in recent years. One of special families of non-linear models is threshold model. Many literatures have shown that even simple threshold model can describe certain types of time series, such as structural change behavior, more faithful than using linear ARMA models. In this paper, we discuss some problems about the threshold model and structural change analysis. Instead of finding the change point, we present the change period concepts on the model- building. An efficient algorithem on constructing the structure change ARIMA models is proposed. Finally, we demonstrate an example about the birth rate of Taiwan, and the comparison of forecasting performance for the structure change ARIMA model with alternative models are also made.