歐盟在與第三國/區域簽訂貿易或投資協定時，因為其市場吸引力，而得以將帶有歐盟價值的規範性議程納入協定中，以實踐自身外交政策的目標。此「規範性權力(normative power)」論述在學界已有廣泛的討論。實務上，歐盟的規範性權力亦不斷透過各種不同的管道，在不同的地區和領域內發揮影響力。歐盟自2013年10月開始，與中國大陸進行全面投資協定(Comprehensive Agreement on Investment，簡稱CAI)談判，目前已完成了第35輪的談判，在2020年底，已達成原則性共識，初期雙方互動熱絡良好。然而，隨著中國「一帶一路」計畫持續往歐陸推進，歐中關係而逐漸出現變化。過去這三年，合作的氣氛轉為對立。2019年歐盟官方首度以「體制競爭對手(systemic rival)」指稱中國，讓雙方關係蒙上陰影。本文欲以歐中CAI出發，了解雙方主要爭點，從規範性權力與布魯塞爾效應的觀點，解析歐中體制競爭的本質，並以此窺探變動的歐中關係。本文最後將以歐盟外交與安全政策高級代表Josep Borrell的態度、歐盟與其他亞洲國家簽訂的IIA、以及目前CAI原則性共識的文本作為參照，判斷歐盟難以從CAI談判中大幅推進其規範性權力。但若與歐盟會員國之前與中國簽訂的BIT比較，仍可看到出歐盟規範性權力的作用。且歐盟顯然已對體制競爭有所警覺，自2019年開始，以經濟政策，作出快速有效的防衛性回擊。然而一旦牽涉到外交政策這種政治層面的問題時，歐盟的反應就顯得緩慢而無力。2021年就新疆人權議題的制裁，可視為一個轉變。但歐 盟共同外交暨安全政策，其制定過程的決策結構，注定會大幅限制歐盟在外交政策上，施展其規範性權力。這將成為歐盟規範性權力面對中國大陸體制競爭時的阿基里斯腳跟，也將是中國最能展現其關係實力之處。

The European Union (EU) has well utilized its market attraction to bring European value based normative agenda into trade or investment agreement negotiations with third country/region, in order to achieve its own foreign policy objectives. This “normative power” theory has had wide discussion among academics. In practice, EU’s normative power has also continuously expanded its influence in different areas via various channels. Since October 2013, EU and China have begun the negotiations on the Comprehensive Agreement on Investment (CAI). After 35 rounds of negotiations, the two parties have reached an agreement in principle by the end of 2020. Meanwhile, the EU-China relations have seen several transitions following the development of Xi Jinping’s grand strategy for the century, the Belt and Road Initiative. At first the two parties showed great amicability toward one another. However, this collaborative atmosphere gradually changed the tone in the past three years. In 2019, the EU official first used “systemic rival” to refer to China, which caused a hitch in the bilateral relations. This article starts with examining the EU- China CAI and pointing out the main arguments of this investment deal. It then takes the approach of normative power theory and the Brussels effect argument to analyze the nature of the EU-China systemic rivalry and to understand the dynamic EU-China relations. The research findings demonstrate that the EU might not be able to push greatly forward its normative power upon China with this CAI negotiations, based on the EU High Representative’s attitude, on the comparative study with other investment agreements that the EU has signed with Asian partners and on the current text of CAI in principle. Nonetheless, if we compare this CAI with the investment agreements that China has formerly signed with EU member states and with other countries, the normative power effects can still be discerned. Besides, the EU has obviously been aware of the systemic threat and has come up with defensive response in its economic policies since 2019. That being said, when it comes to common foreign policy, the EU’s reactions appear to be slow and weak. The sanctions on China for human rights abuse in Xinjiang in March 2021 could be seen as a change. However, EU’s common foreign policy decision-making structure itself is set to largely limit its normative power. This could become the Achilles’ heel of the EU normative power when facing China’s systemic threat, where Chinese relational power would find the space to stretch its wings.