2004 年及 2007 年歐盟兩次東擴後已有 27 個會員國，但目前仍有許多國家期望未來可以加入歐盟。對歐盟來說，繼續擴大歐洲穩定與民主區有助於歐洲大陸局勢之穩定，然其負面效應則是過多會員國可能有礙於更深層次的整合與有限資源應如何有效分配等問題。因此，歐盟對其鄰近國家採取一系列相關政策來整合目前歐盟與這些地區之互動，其主要政策工具即是歐盟睦鄰政策之推行，本文試圖釐清歐盟睦鄰政策初步實踐之效果。作者認為，睦鄰政策做為歐盟外交政策工具之一，其主要核心目標在於提供誘因協助夥伴國政治經濟發展、推展歐盟價值。從烏克蘭之案例分析可知歐盟睦鄰政策有協調整合歐盟處理對外事務之功效;對外則提供烏克蘭發展路徑圖，讓有心符合歐盟期望的夥伴國得以遵循特定發展路徑。不過本文也指出歐盟睦鄰政策可能潛在困境，該困境主要來自歐盟與夥伴國共識之不對稱，本文認為由於歐盟現階段內部共識不足、未提供有效且明顯之資源協助夥伴國，以及歐盟刻意採取模糊策略，未明言夥伴國未來能否取得正式會員國之身分，這可能無法滿足烏克蘭最終期待，若歐盟長期對此問題處理不當，將可能導致未來夥伴國對歐盟產生信心危機，並進而影響雙方互動關係與地緣政治發展。

There are 27 member states within the European Union after enlargements of 2004 and 2007; many others are still trying to join the EU recently. The inclusion of more states is conducive to the expansion of stability zone in the European continent but it will be at the cost of closer EU integration and resource distribution. The European Neighbourhood Policy is designed for enhanced cooperation after the fifth enlargement between EU and its partner countries and this article tries to explore the innate nature of policy goals and its practices. The author argues that the ENP and Common Foreign and Security Policy co-constitute the core of EU’s external actions in the sphere of promoting political and economic transformation around neighbour countries. The case of Ukraine depicts that the ENP acts as an internal cohesion on one side and provides policy instruments as roadmaps of development on the other side. Their major obstacle lies in the “vagueness in membership” and it could lead to putting a damper on Ukraine’s zeal to join the European community; it will have negative impacts on regional integration and possible geopolitical development.