2001年九一一事件後，無論是以聯合國為首的國際組織所採取的種種措施，或是國際社會各國自行訂定的處理對策，都可視為促進國際法形成與發展新型法規範的重要因素。本文嘗試探討二十世紀末以後，國際社會採取的對策與國際法如何評價國際恐怖主義，以及其對國際法的理論構造和國際法規範的基本架構所帶來的影響。至二十世紀爲止，以主權國家並存爲基本架構的國際法「國家性」原則，很有可能產生本質上的改變。但也必須指出觀察其後國家實踐與國際法理論的發展，對全體國際法體系而言，國際恐怖主義問題應該沒有帶來當初預期的變化。正如國際法規範體系所持續證實，無論是關於自衛權、國家責任法、武力紛爭法、國際刑事法等範疇，國際社會一方面維持「國家性」的基本構造，另一方面也兼備了面對國際恐怖主義應有的柔軟性及強韌性。

This essay tries to inquire after the end of 20th century, how did the countermeasures adapted by international society and International Law evaluate International Terrorism. And also we'll talk about their effects on International Law theory structure and the basic mechanism of International Law. In this essay we'll discuss that up until the end of 20th century, the principle of Statehood; having sovereign countries coexist as their basic mechanisms would probably change essentially. We also need to point out that for the whole International Law system, observing the realization of countries and the development of International Law theory didn't bring the expected change to the problem of international terrorism. The International Law system has constantly proved in terms of categories such as right of self-defense, National Responsibility Law, Military Force Disputes Law and International Criminal Law, on one hand the international society maintains the basic mechanism of Statehood, on the other hand it also has both the flexibility and tenacity to face international terrorism.