With the globalization of the economy, the fuzzy language in business English negotiations is widely used. The motivation for negotiators to use fuzzy language is not to hide information, but to convey information more clearly. This article attempts to divide business negotiations into three stages: the beginning, the process, and the end. With fuzzy language in business negotiation as a corpus, this paper studies how people adapt to different contextual factors to regulate fuzzy language in the process of business English negotiations under the guidance of relevance theory so as to achieve the optimal contextual effect with the minimum effort.