1 IntroductionBusiness English can be regarded as an application of English language in commercial occasions, aiming at enabling speakers to communicate and interact effectively using the most correct and clearest business language. Business English Correspondence is an important carrier of international commercial activities which is used to deli ever information, address commercial issues and as a way of communication. Lexicon is an important factor of a passage. In the writing of business English correspondence, we should pay particular attention to the selection of lexicon. Different words may carry different meaning and even the mood of them can be very distinct. Therefore, it is of great necessity to do research of the features of lexicon in the writing of business English correspondence.This thesis attempts to do some researches on the following subjects: To have a good knowledge of characteristics of lexicon in business English correspondence. To make sense of the reason why the business English correspondence have such requirements of lexicon. To provide some suggestions that learners can improve their writing skills. 2 Description of Business English correspondence 2.1 Definition of business English correspondenceNowadays more and more people choose to work in companies and do commercial work. As China joined the WTO, enterprises are all choosing to open their markets and expand them into the international world, thus making English inevitably become the most used language in the world. And in this way a new subject appeared that we call it “business English”. In terms of business English, we refer to the language used in order to adapt to the job market whose contents include a lot of aspects (Kansi, 1983; 134). Unlike the general English learners, people who learn business English are more targeted and specialized. Business correspondence means the act of communicating by means of correspondences or the correspondences between correspondents (曹菱, 2000; 87). It is the main way for traders to do business, exchange commercial information and consult and give answers to commercial questions in international trade. Besides, it is a reflection of different cultures, social backgrounds and representative of interests of both parties of a trading activity. Business English correspondences is different from personal correspondences, for it is more formal and can be a legal document for both enterprises to do business transaction and deal with commercial disputes. This is a serious problem that business English correspondence writers should pay attention to.Different from the state correspondence or personal correspondences, business English correspondences has its own characteristics both in the article style and language (Ober, 1998; 98). In particular, it is high demanded of the correctness and standards of language. The business correspondence should be clear, concise, concrete, and of courtesy in language.2.2 Assortment of business English correspondenceIt can categorize business correspondences into three kinds. They are as follows: The first kind is in accordance with the letters content. We have invitation letters, selling letters, employing letters, and etc. In terms of the role the business letters plays in commercial activities of enterprises, we have negotiating letters which aims at address a dispute, friendly letters which is used to keep a friendly touch with another company, and etc. The last is the correspondence, which is used to give some information .The information may be good or bad. In a word, we can classify the business correspondences from different perspectives just as the way mentioned above. Sometimes, each kind is not so isolated from others. Besides we have mentioned above, there are also many kinds of business English correspondences such as letters for setting up business relationships, conclusion of business, sales contract or confirmation, sales promotion, order and fulfillment, products shipment, shipping advice, insurance, claim, asking for an agent, processing trade, compensation trade, and etc.2.3 Function of business English correspondenceToday it has come into an information society with the development of information technology and the Internet. Business English correspondences plays an important part in international trading activities due to its courtesy, completeness, conciseness and other good features in order to obtain and deliver information, make effective communication, address related issues in commercial activities and maintain good and normal operating relations. Business correspondence means the act of communicating by means of letters or the letters, which pass between correspondents (曹菱, 2000; 76) .It is the main way for traders to do business, exchange commercial information and consult and give answers to commercial questions in international trade. Besides, it is a reflection of different cultures, soci