2001年9月11日發生在紐約與華府的恐怖攻擊事件，在美國對阿富汗塔利班政權進行軍事報復後，已經實質改變後冷戰時期以來的國際安全架構。本文嘗試從恐怖主義的發展脈絡，論述其對國際安全的影響，尤其是透過分析冷戰以來美國反恐怖主義政策，從以國家為中心到以區域為中心，再演變為以全球為中心的戰略包圍，對911事件後國際安全環境的可能轉變進行預判。同樣的，在轉變中的國際安全環境裹，中共與臺灣的角色也是本文的焦點。雖然國際環境逐漸在轉變，但兩岸均小心翼翼的跟隨美國反恐戰爭的腳步，雙方均不願破壞兩岸關係的基本架構。因此，轉變中的國際環境，不必然會影響兩岸關係。

　　　　　The September 11 attacks in New York and Washington, D.C. have substantially changed the international security framework that established during the Post-Cold War era. The emergence of issue-oriented international coalition will substitute the traditional global issues-oriented cooperation pattern. This paper tries to analyze the impact of terrorism development on international security. Particularly, it argues that U.S. anti-terrorism policy has changed from state-centered to area-centered strategic containment, and further transformed to global-centered strategic containment, so that we can anticipate the possible change of international security environment after the 911 attacks. In the same way, how PRC and Taiwan play their own roles is also the focus of this paper. This paper argues, though the international environment is changing, both sides of Taiwan Strait will cautiously follow the U.S. anti-terrorism policy, and try their best not to violate the basic framework of cross-Strait relations.