自從1973年主要工業國家紛紛放棄可調整固定匯率制度，改採浮動匯率以來，通貨替代的命題一直是許多國家注意的焦點。其主要的影響可分為下列二方面來說明： 　　1.通貨替代的存在，將引起匯率的大幅波動。 　　2.通貨替代的存在，將一國的貨幣干擾傳遞至其它國家，造成國際間各國貨幣政策有相依性，降低當局控制本國貨幣的自主性。 　　本文嘗試以資產組合相對報酬率之觀念，建立短期動態通貨替代實證模型，利用民國68年2月至民國83年12月之月資料，來探討台灣是否存在"通貨替代"的現象。得到下列的結論： 　　1.在整個樣本期間的估計結果，我們獲得解釋變數的係數符號與理論要求一致，且係數估計值顯著，而殘差項亦大致符合OLS基本假設中的規定。 　　2.從半彈性的估計值中，我們發現：M1A與美元的持有比例對實際匯率變動率之半彈性估計值，顯然比M1B與美元的持有比例對實際匯率變動率之半彈性估計值為大，這表示當匯率變動率發生變化時，人們較易改變其M1A與美元間的通貨組合。 　　由以上的結果，本文得到台灣的確存在"通貨替代"的現象。

Abstract The controversy about the monetary regime of the EC between the Britain and the other member countries made economists to study currency competition and currency substitution widely. This dissertation constructs a one-good, two-currency Brock model in discrete time. In the determinate model, we show the Gresham’s Law results as those in Weil’s. And we demonstrate the existence and uniqueness of a class of first-order Markov stationary sunspot equilibria. The existence of sunspot equilibria expresses another situation of currency competition that future situations may depend on the possibility of people’s expectations, not the growth rates of currencies and tries to provide another explain for the phenomena above.Britain and the other member countries made economists totudy currency competition and currency substitution widely .his dissertation constructs a one - good , two - currencyrock model in discrete time . In the determinate model , wehow the Gresham' s Law results as those in Weil's . And weemonstrate the existence and uniqueness of a class of firstorder Markov stationary sunpot equilibria . The existencef sunspot equilibria expresses another situation of currencyompetition that future situations may depend on the possibi-ity of people' s expectations , not the growth rates of cu -rencies and tries to provide another explain for the pheno -ena above .