軍事干涉(military intervention)是國家或國際組織以軍事方式介入或干涉其他國家內部事的行為。聯合國憲章雖然禁止武力使用與武力威脅，然而自從聯合國成立以來，受冷戰與大國權力關係影響，聯合國安全理事會無法有效積極維護國際安全與和僤，因此大國的軍事干涉某種程度竑而成為維護區域秩序的手段，但有時也成為強國欺凌與干涉其他國家事的籍口，以所有關軍事干涉的國際法規定可謂是相關國際安全規尸最受爭議的領域。 本文將探討各種軍事干涉行為的國際法規範、國家實踐與學者主張，作者並將提出本文的觀點，以深入分析現今國際社會對於軍事干涉的規範架構與內容。文章將分別討論國際法上不干涉原則的內容與發展以及聯合國軍事干涉行動外，將討論三項主要軍事干涉行為，分別為：介入他國內戰的軍事干涉行為、協助他國境內民族自決運動之運事干涉行為、以及為保護僑民而採取的軍事干涉行為。本文將整理呈現各項軍事干涉的特性與不同主張，作者並將提出本文的觀點。

　　　　　Military intervention means that state intervenes or involves other state's internal affairs by military means. UN Charter prohibits state's any use of force or threat of force in its relations with other national. However, ever since the establishment of the United nations, due to the Cold War and power politics between major countries, the Security Nations, due to the Cold Ward and power politics between major countries, the Security Council is not very effective in dealing with cases affecting international and regional peace and security. Some major powers therefore made use of various forms of military intervention to implement their foreign policies. Sometimes those cases of military intervention were legal excuses of power politics, but sometimes there were certain legitimate reasons. The paper will discuss military intervention in international law, including international regulations concerning military actions, principle of non-intervention, and state practices related to military intervention. UN military actions is also a major discussion focus of the research, together with the analysis of the principle of non-intervention. Three different forms of military intervention will be addressed as follows: military intervention in civil war, military intervention in supporting self-determination, and military intervention to protect nationals.