Abstract: Vagueness, as an intrinsic feature of language, has been given increasing attention by the scholars. First this thesis introduces the characteristics of vagueness as well as the basic concept of cooperative Principles, and then analyzes the functions of vague language in business negotiation according to Cooperative Principle. The thesis reaches the conclusion that in the business negotiation, vague language has also become a strategy and method; its function can be shown in four aspects: making the language euphemized and keeping the faces of both sides, avoiding absoluteness and making the language flexible, leaving some leeway for others, enhancing persuasion and making the negotiations succeed. A great amount of vague languages in business negotiation is the result of conscious use by negotiators and the result of the contextual and language structure adaptation.

Key words: business negotiation; vague language; Cooperative Principles; function

摘要：  语言的模糊性作为自然语言的一种本质属性，近年来受到越来越多学者的关注。论文首先介绍了模糊语言的特点,以及合作原则的基本概念, 并就合作原则分析了商务谈判中模糊语言的应用。通过研究发现，商务谈判中，模糊语言也成了一种策略和手段，其作用表现为四个方面:委婉含蓄，保留双方面子；避免绝对，使语言灵活严谨；留有余地，避免僵局；增强说服能力，促进谈判成功。商务谈判中大量模糊语言是谈判者有意识使用的结果，也是语境与语言结构动态顺应的结果。

关键词：商务谈判; 模糊语言; 合作原则; 功能