本文先討論GATS最惠國待遇原則的法定例外，並以最惠國待遇豁免機制為檢驗焦點，進行量化與質化分析，強調在經濟整合協定中的服務業市場開放優惠待遇。探討服務貿易原產地問題的主要實益在於理解如何捍衛「不歧視原則」的大門。在「不得」歧視的情形下，我們必須適用原產地規則以決定會員國是否遵守規定；在依法「得」歧視的情形下，我們更需要原產地規則來判斷受惠服務或服務提供者的範圍。關於「服務本身來源國」及「服務提供者所屬國籍」的認定問題，本文以法釋義的研究方法檢視GATS及區域貿易協定相關規範，並分析WTO爭端解決中的實務見解。本文認為，爭端解決小組認定服務來源的定義操作方式，確實忽略跨境服務的真正價值創造者，也可能無法發覺商業據點的真實控制者。此「極簡化」取徑使服務貿易原產地規則流於過度簡化的論述。然而，如何建立精確標準以判斷所謂「服務增值」或「智識投入」，技術上極為困難。此外，觀察各國最惠國待遇豁免表，歧視待遇的正當性常與管制目標緊密相扣。由於跨部門水平規範無法顧及不同產業的政策目標，故「把關」功能有其侷限。建立「部門別」原產地規則將有助於實現管制政策。 The method the author finds most suitable for presenting the necessary analysis of the issue is to highlight, by both quantitative and qualitative approaches, the key aspects of the MFN exemption mechanism, as it applies to trade in services. An important question in the design of multilateral or regional trade agreements covering services is to what extent non-members benefit from the trade preferences that are negotiated among members. This question is resolved through rules of origin for services trade—the gatekeeper of the principle of non-discrimination. This research employs the textual/plain meaning approach to discuss the criteria determining “the origin of a service” and “the origin of a service supplier,” and then further discusses the relevant interpretations provided in Panel and Appellate Body reports. The author is of the view that any rule of origin for services based mainly on the nationality of the service producer will not attempt to trace the origin of “substantive inputs” into the traded services, and such methodology may be criticized as oversimplified. However, a rule of origin for services that attempts to satisfy the underlying economic rationale (e.g., to incorporate the concepts of “value-added” and “intellectual input”) will be extremely difficult to formulate and to administer. Thus, this paper in the final part points to the need to develop sector-specific rules of origin to address the regulatory issues, and argues that it is better to establish tailored and sectoral rules of origin for services trade.