Abstract：In Lakoff’s Metaphors We Live By, he pointed out that metaphors exist not only in our languages but also in our minds, actions and daily life. Conceptual metaphors are closely related to human’s cognitions. As one way to recognize and understand the world, conceptual metaphor can effectively reveal people’s thoughts and opinions. So metaphor is not only a rhetorical device, but also an approach to enrich our understanding of the whole world. Political speeches are very important cultural phenomena in western society and are playing very important role in political life. So analyzing political speeches is of great significance to scan relationships between languages and thoughts. 

　　　This research is based on the conceptual metaphor system of George Lakoff, the founder of cognitive linguistics. The author makes researches in the context of common metaphor phenomena in speeches. Combing with the three kinds of classification (structural metaphor, orientational metaphor, ontological metaphor) and by discussing about speeches in four universities (the Notre Dame University, the Cairo University, the Fudan University and the Michigan University), the author tries to reveal the conceptual metaphor s in these speeches and reveal the relationships among metaphors. Then the author tries to analyze how these metaphors help the speakers to persuade the audience and reach their goals. 

　　　By summarizing and inducing the above four public speeches, the author has summed up six kinds of metaphors that appear most frequent. They are journey metaphor, human metaphor, nature metaphor, war metaphor, student metaphor and stage metaphor. Meanwhile, as to differences in speeches in different campuses, the author has made deep study and got three main reasons. First is difference in audience; second is the difference in cultural backgrounds of these four universities; third is difference in purposes of speeches.

　　　By analyzing theses above four texts, this article made a primary research about metaphor’s function on persuading the public and arousing emotion; meanwhile, this article has also reached a primary conclusion about the relationship between metaphor and politics. Metaphor plays a crucial role in expressing political concepts and conveying emotions. When speakers of political speeches use metaphor to well demonstrate their aims, speeches can achieve better results with fewer efforts. According to different event backgrounds, adjustments and changes should also be made to metaphors to act in concert with different aims in different occasions. 

Key words: conceptual metaphor, speech, politics

摘要:Lakoff和Johnson在《我们赖以生存的隐喻》一书中提出，隐喻不仅普遍存于我们的语言之中，而且存在于我们的思维、行为和日常生活之中。概念隐喻，与人的认知关系密切，作为认知世界的—种手段，能够揭示人们的观点和思想。所以，对隐喻的研究，不仅是研究一种修辞手法，更是丰富我们理解世界的途径，而政治演说是西方社会—种重要的文化现象，在政治生活中扮演着重要角色。所以，研究政治演说中的隐喻现象，对于审视语言和思维的关系有重要的意义。

　　　本课题的以认知语言学创始人George Lakoff的隐喻认知体系为出发点，以政治演讲中频繁出现的隐喻现象为研究背景，结合Lakoff对隐喻的三种分类（结构隐喻、方位隐喻和本体隐喻），通过对美国总统奥巴马在四所大学（美国圣母大学，埃及开罗大学，中国复旦大学和美国密歇根大学）所发表演讲的研究，揭示其中的概念隐喻以及它们之间的联系。

　　　通过总结归纳在四所大学校园的公共演讲中，作者统计了出现频率最高的六种隐喻，分别为1）旅途隐喻；2）人类隐喻；3）自然隐喻；4）战争隐喻；5）学生隐喻；6）舞台隐喻。同时针对不同校园的演讲，隐喻现象存在的差异，作者得出了三个主要原因1）演讲的听众不同；2）学校的文化背景不同；3）演讲的目的有具体区别。

　　　通过以上四篇文本的分析，作者对这些政治隐喻在激发情感、等说服大众方面的作用进行初步研究；同时也对隐喻和政治的关系得出了初步的结论：1）隐喻在表达政治概念和传达情感方面有重要的作用，当政治演讲者把自己的目的巧妙地通过隐喻表达，政治演讲可以达到事半功倍的效果；2）根据不同的事件背景，隐喻也应该做出适当的调整、变化，以配合演讲者在不同环境下的不同意图。

关键词：概念隐喻；演讲；政治