Abstract:With the expansion of economic activities on an international scale, English business correspondence became an indispensable part of business transactions. Business writing plays an important role in building and developing business relationships, cooperating with business partners, dealing with transactions, and maintaining goodwill. Politeness or courtesy is an indispensable principle in English business letter writing, but it is very complicated for it is often influenced by various factors which are quite often implied or hidden between the lines, so it is not easy for business letter writing learners to master and handle this principle. In order to solve this problem and find the basic rules of politeness phenomenon for English business letters, the author conducts this study. The author aimed at explaining Leech's Politeness Principle used in English business correspondence to find the hidden rules of being polite in English business correspondence. The further purpose is to improve the learning efficiency of English business letter writing.

Key words: Leech; Politeness Principle; English business correspondence; Politeness       strategies

摘要：随着国际经济的蓬勃发展，英语商务信函逐渐成为贸易活动中不可或缺的一部分。商务信件作为商业交流手段之一，在建立和维持商业联系，合作买卖与保持良好关系方面发挥着重要作用。礼貌是英语商务信函中一个不可缺少的原则，但是它很复杂，因受到各种因素的影响，而往往这些因素都隐藏在字里行间，不易被注意。这使得英语商务信函学习者很难掌握和处理信函中的礼貌问题，为了解决这一问题，找出英语商务信函中礼貌原则的规律，笔者进行了这一话题研究，旨在通过运用Leech 的礼貌原则在英语商务函电中的分析，从而找出隐藏在商务信函深处的潜在规律，以期提高英语商务信函学习者的学习效率。

关键词：Leech； 礼貌原则；英语商务信函； 礼貌策略

注：本文全文为英语所写的英语论文。只有摘要是中英语写的，全文为英文。