Politeness is a kind of phenomenon in language communication, and it is also an important subject in the study of Pragmatics (Madden court, 1995). Many western linguists, such as J.L. Austin, H.P. Grice, J.R. Searle, G. ,Leech, Brown and Levinson etc, who all had made great contributions to pragmatics. Besides, they had made a series of researches on Politeness phenomenon in language communication from the perspective of pragmatics, which provided a solid theoretical basis for politeness principle. H.P. Grice (1975) put forward the principle of cooperation in language communication. In 1976, he put forward the theory of conversational implication, which was of important directive significance to the use of polite language. Brown and Levinson (1978) raised the issue of "face" and the face-threatening act of communicative language. In 1979, J.R. Searle went on to propose the theory of indirect speech act, and to explore the way of expression of euphemism. 

English business correspondence is a kind of letter, which takes English as medium, and promotes the smooth development of business activities for the purpose, which covers the content related to many areas of business. It plays an active role in exchanging ideas, transferring information, negotiating business, enhancing understanding, promoting economic and trade exchanges and so on. Business English, whose language is novel and unique, and has the modern English breath, one of the biggest features of the language style is using polite language. With China's entry into WTO and the continuous deepening of reform and opening up, China's economic and trade and cooperation with the world has become day by day frequent, business English is becoming extremely important, but also by more and more extensive attention. In recent years, many universities have set up Business English as a major, business English language teaching has attracted the attention of many English teaching workers and experts engaged in foreign trade. Chen Jianlin(2003), Li Ruifang(2003), Ding Hengqi(2004), and so on, who carry on the research of different levels on the reform and the establishment of business English curriculum, the skill of language use, translation and other issues. Their discussion and Research have positively influenced business English teaching and practice Inspired by them, this paper attempts to discuss the application of politeness principle in Business English from the perspective of pragmatics, hoping to provide some enlightenment for the writing and teaching of business English.