Abstract：The concept of “Politeness Principle” (PP) was first put forward by Leech in his book Principles of Pragmatics in 1983. Besides, he summed up and classified Politeness Principles in communication activities from the aspects of Pragmatics and Interpersonal Rhetoric. It provides some standards that can be referenced and followed by people for the correct use of courtesy, which includes Tact Maxim, Generosity Maxim, Approbation Maxim, Modesty Maxim, Agreement Maxim and Sympathy Maxim.

　　　In this thesis, Politeness Principles are employed to analyze the discourse of English business conflictive correspondence, which are used for delivering unpleasant news, from the aspect of fuzzy language, subjunctive mood, passive voice and impersonalization. The author tries to find out how Politeness Principles are applied in business conflictive correspondences to achieve communicative purpose. 

　　　This thesis consists of four chapters. Chapter one serves as a brief introduction, including  politeness principle, English business conflictive correspondence. Chapter two is a literature review which contains previous study on politeness principle and English business conflictive correspondence. Chapter three introduces the application of politeness principles in English business conflictive correspondence. Chapter four is a conclusion including major findings and limitations.

Key words:  Business English correspondence  conflict  Politeness Principles 

摘要：利奇在1983年出版的《语用学原理》中首次提出了“礼貌原则”这一概念,并从语用学和人际修辞学角度对交际活动中的礼貌原则进行了归类和分类，为人们礼貌用语的正确使用提供了一个可借鉴与遵循的标准。它包括六大方面：得体准则、慷慨准则、赞美准则、谦逊准则、一致准则和同情准则。

　　　本文从模糊语、虚拟语气、被动句和非人格化角度,尝试应用礼貌原则理论对英语商务函电中传递坏消息的冲突类信函进行分析，以揭示礼貌原则如何在冲突类商务英语信函中达成交际目的的。

　　　本文分为四个章节。第一章主要介绍了礼貌原则、商务英语冲突类信函和本文的内容。第二章是文献综述介绍了当今国内外对礼貌原则和冲突类英语商务信函的研究现状。第三章则介绍了礼貌原则的标准在冲突类英语商务信函中的应用。第四章是对全文的总结，主要包括本文的主要成果和不足之处。

关键词：商务英语信函；冲突；礼貌原则