美国总统每周演讲是一种重要的政治语篇。如何处理演讲中所涉及的复杂人物关系是总统在演讲中达到劝说目的的主要途径。本文运用系统功能语言学理论,结合评价系统介入语言资源,以主体间性为视角,分析奥巴马每周演讲话语情态的选择。研究发现,在情景语境、文化语境和意识形态的共同作用下,奥巴马每周演讲语言的情态蕴涵丰富的人际意义,既表达了奥巴马对共和党的抨击与指责,又显示了奥巴马对美国民众的拉拢与融合及与共和党合作的意愿,更为重要的是这两股具有消极与积极人际意义的情态运用成为奥巴马每周演讲语篇在主体间性基础上的多声介入标记,情态的量值级差暗示了奥巴马对人际对话可能出现的声音的包容程度。 Weekly U.S. presidential address is an important political discourse. How to deal with the complex relationships involved in the speech is the main way for the president to persuade him in his speech. In this paper, we use the theory of system functional linguistics, combined with the evaluation system to intervene in language resources, and from the perspective of intersubjectivity, we analyze the choices of Obama’s weekly discourse modality. The study finds that under the joint action of context, context and ideology, Obama’s weekly speech language contains rich interpersonal meanings. It not only expresses Obama’s criticism and accusation against the Republicans, but also shows that Obama has a great influence on the American people And the willingness to cooperate with the Republican Party. What is more important is that these two negative and positive interpersonal modalities are used as the multi-acoustic markers of Obama’s weekly speech discourse on the basis of intersubjectivity. The amount of modality The difference in value implies Obama’s tolerance for the possible voices of interpersonal dialogue.