本文之主要目的為:探討雙元匯率在有特殊限制下,其對經濟穩定性之影響(即對物價、利率產出、商業匯率及金融匯率的穩定作用)。故本文擬修改Froot and Obstfeld(1991)之模型為包含實質面隨機干擾項的模型;再結合目標區的研究方法,來探討以下之問題:當經濟體系面對實質面之經濟干擾時,中央銀行如何在商業匯率目標區政策、商業匯率自由浮動政策政策下作選擇。期在此修正模型下,發現一能使經濟穩定之最適政策指標。本文之結論為:和傳統理論認為商業匯率和金融匯率穩定係互相抵觸的說法不同,就目標區理論而言,在某些狀況下兩者之穩定是相輔相成的;而係數Ω/sub 0/之正負扮演關鍵性的角色。 Based on a simple stochastic macro model, this paper addresses the relative stabilizing performance of dual exchange rates system from the viewpoint of target zones. Contrast to the conclusion in dual exchange rate literatures, upon the shock of a change in commodity production, we find that the inverse movement in these dual rates is not always be hold under the commercial rate target zone policy. The elasticity of some specific factors is the crucial point for the desirability of targeting commercial rate: with Ω/sub 0/>0, this policy tend to lower the variability of prices, interest rates, and commercial rate but raise the variability of output, financial rate's variability is uncertain. However, with Ω/sub 0/<0, the policy will lead to a smaller output, commercial rate, and financial rate fluctuation at the expense of larger price and interest rate fluctuations.