Presupposition， mutually known by interlocutors， exists prior to uttering something， studies of which has been experiencing three phrases， that is， logic presupposition， semantic presupposition and pragmatic presupposition. The first stage was in the field of philosophy. The concept of presupposition was initially wrestled with to solve the problems about the nature of reference and referring expressions by philosopher Frege， who proposed that “If anything is asserted there is always an obvious presupposition that the simple or compound proper names used have a reference” （Levinson， 1983： 169）. What followed was semantic presupposition at which presupposition was treated as a semantic notion to reveal the relation of sentence and proposition. Because entailment also deals with semantic relation， it is always compared with semantic presupposition. In fact， the two are different from each other. According to Yule （2000： 25）， “An entailment is something that logically follows from what is asserted in the utterance. Sentence， not speakers， have entailment”. While “A presupposition is something the speaker assumes to be the case prior to making an utterance. Speakers， not sentences， have presuppositions”. Based on this distinguish， presupposition can be sensed as a dynamic process instead of a static sentence relation. Consequently， developing to the third phase with he rise of pragmatics， presupposition has been found to be highly sensitive to context and then pragmatic presupposition was put forward （Chen Xinren， 2009： 92）. Compared to semantic presupposition， pragmatic presupposition differentiates in mutual knowledge， segmentation way and truth value. While Cong Richou and Qiu Wei （2016） viewed that the both are characterized by the commonality derived from their intersection in mutual knowledge and defeasibility.
　　As to the classification of pragmatic presupposition， different linguists have diversified categorizations. For example， Yule grouped it into existential presupposition， factive presupposition， non-factive presupposition， counter-factual presupposition， lexical presupposition and structural presupposition （Chen Xinren， 2009： 99）. In accordance with Chen （1998）， pragmatic presupposition can be categorized into factive presupposition （stating facts）， belief presupposition （involving beliefs or attitudes）， state presupposition （dealing with emotions or feelings） and behavior presupposition （addressing behaviors） based on its performance in utterance.
　　References：
　　[1]Levinson， S. C. （1983）. Pragmatics [M]. Cambridge University Press： CUP.
　　[2]Yule， G. （2000）. Pragmatics [M]. Shanghai： Shanghai Foreign Language Teaching and Research Press.
　　[3]陳新仁.新编语用学教程[M].北京： 外语教学与研究出版社，2009.
　　[4]陈新仁.广告用语中的语用预设[J].外国语，1998（5）： 54-57.
　　[5]丛日珍，仇伟.语义预设与语用预设的重叠性与互补性 [J]. 现代外语，2016（5）：594-604.
　　【作者简介】王美丽，兰州交通大学。