Abstract:With the continuous advance of the global economic, trade integration and the increasingly competitive international trade, English business correspondence is playing an increasingly important role in the international business activities. Meanwhile, the quality of an English business letter reflects the professional degree of one enterprise or business institution and contributes most to establish a corporate image. A polite and well-written English business letter not only undertakes the partial responsibility of establishing business contact, but also enables getting twice the result with the half the effort. 

　　Politeness principle has an important role in guiding the English business correspondence writing. You-attitude is widely regarded as the first principle among the politeness principles. An English business letter, which is of a good quality, is quite particularly stresses about the usage of You-attitude besides the correctness of vocabulary and grammar. The appropriate using of You-attitude can make the readers feel the sincerity and thoughtfulness of the writer. Therefore, it may directly contribute to the success of the transaction.

　　You-attitude is considered as the foremost principle for guiding business letter writing. Its application in different type of business correspondence is mainly discussed in this thesis. 

Key words: You –attitude; English business letters; Politeness principle

摘要:随着全球经贸一体化的不断推进,国际贸易的竞争日益激烈,英语商务信函在国际商务活动中起着越来越重要的作用,常常是促成一项业务的关键环节,同时,商务信函的质量也反映了一家企业或商务机构的专业程度,对树立企业形象起到了重要作用.一封彬彬有礼、条理清晰、言简意赅、用词恰当的信函不仅能使我们在商务交流活动中事半功倍,还担负着建立、加强业务联系的重任.

　　　礼貌原则在商务信函写作方面具有非常重要的指导作用,其中,You-attitude被广泛认为是首要原则,在实际商务信函交际中起着至关重要的作用.一则好的商务英语信函除了词汇、语法准确无误,对You-attitude的运用也是相当讲究的.若运用恰当,将使读信人感受到撰写者的诚意与周到,进而可能直接促成交易的成功.

　　　本文通过对You-attitude的定义和相关理论进行概述以及对英语商务信函进行分类，从多个角度和层面分析You-attitude写作原则在英语商务信函中的体现和功能，认为You-attitude 在实现商务信函交际目的中起着至关重要的作用，因此应把You-attitude 作为指导商务信函写作的首要原则，并结合实例着重讨论You-attitude在不同种类的商务信函中的应用。

关键词:You-attitude;英语商务信函;礼貌原则