商务英语信函在国际贸易活动中起着越来越重要的作用。它实质上是一种书面的商洽方式。这种书面的商洽方式与桌面商洽方式一同推进商务协作的顺利进行。以“礼貌原则”和“面子保全理论”为理论基础,分析了在外贸函电的语言表达和信体布局中如何运用礼貌策略。 Business English letters play an increasingly important role in international trade activities. It is essentially a written negotiation. This written approach to negotiating with the desktop business approach to promote the smooth conduct of business collaboration. Based on the theory of “politeness principle” and “face preservation theory”, this paper analyzes how to use politeness strategy in the language expression and the credit distribution of foreign trade correspondence.