台灣因為內需市場小經濟都是以出口為主要，且因海島地形四面環海許多生產要素及商品都需仰賴進口，以上兩個原因都可以窺得國際貿易對台灣來說是重要的經濟活動，其中進出口貿易額更是嚴重影響台灣GDP。本文以國際收支角度切入，探討台灣與美國之間匯率、進出口貿易、資本流動、利率之間相關性，本研究使用Johansen共整合檢定來探討長期穩定關係下變數的特徵，以實證數據結果來看，可以總結出以下三點：首先經常帳與匯率兩者之間，經常帳受匯率影響較大，匯率受經常帳影響較小；其次資本跨國移動跟匯率相關；最後匯率沒有遵照市場機制，央行對匯率干預的程度比想像中大。 International trades are essential economic activities in Taiwanese economy; especially exports and imports occupy a large proportion of our GDP. This research uses the balance of payment to evaluate the market efficiency of foreign exchange rates. We concentrate on the manipulation by the central bank in foreign exchange market. Through balance of payment, we investigate the relationship among capital mobility, foreign exchange rates, exports and imports, interest rates. We use Johansen cointegration to their long run relations. Based on the empirical data, we have three concluding remarks: (i) first, the current account and the exchange rate have large influence on the exchange rate, and the exchange rate is less affected by the current account. (ii) Secondly, the relationship between capital outflow and exchange rate is correlation. (iii) Finally, the exchange rate in the long-term relationship is difficult to converge, indicating that the exchange rate does not follow the market mechanism.
