本文以美国总统奥巴马就对利比亚军事行动的政治演讲为研究对象，分析了语言的人际意义在奥巴马的军事政治演讲中的实现。此类研究目的在于了解演讲者如何运用特定的语言元素去表达他的政治信念和目的，建立听众与他之间的相互关系，以及影响并改变听众的信念和价值观念。本研究以韩礼德的功能语言学为理论框架，从语气，情态和人称三个方面分析了奥巴马的五篇政治演讲。分析发现，奥巴马主要采取了陈述句形式进行演讲，以此来扮演一个信息提供者的角色。这种语气形式使得奥巴马的演讲更加令人信服和客观。同时，通过大量地使用中量值的情态动词、语气连接词和第三人称复数词“我们”，奥巴马强调了自己观点的可信度，拉近了与听众的距离，将为自己树立了一个与听众具有共同利益但又权威的形象，表明自己将会代表美国人为他们的共同利益而奋斗。虽然本研究在深度方面还有所欠缺，但本研究在很大程度上有助于读者提高对政治演讲的批判性思维，使其能掌握更有效的交流沟通方式，并将其更好地运用于未来的交际活动之中。

This study sets out to explore how interpersonal meaning is realized in Obama’s political speeches on the military operations to Libya on the clause level. Such study is important in order to investigate how the political speaker uses certain linguistic elements to convey his political beliefs and judgment, to establish the relationships between the audience and himself, and to influence the change of the audience’s beliefs and values. Based on Halliday’s Systemic Functional Linguistics, this study has analyzed Obama’s five speeches from the perspective of the mood system, the modality system and the person system. From the analysis, it can be concluded that Obama delivers his speeches mainly in declarative mood, taking the speech role of an information-giver, in order to convince the audiences on an objective and formal basis. Meanwhile, through the frequent use of median-value modal operators, mood adjuncts, and plural first person pronoun “we”, Obama successfully persuades the American people in a trustful manner, establishes a common ground for both of his audiences and himself, and becomes an authoritative representative of the American people. However, the size of language materials is small and the analysis is mainly focused on the clause level, which have limited this study on a deeper interpretation. Still, it is hoped that the findings of this study can help readers develop a critical thinking about the political speech and learn a more effective way in communication.