| The idiom is the springboard for many scholars in their culture study. The domestic study of idioms reached a new phase in its idea proofing while western linguists give further and penetrating research into idioms deeper in their physical function. The result of these researches is that the relevance between language and culture are in some extent clarified by all kind of studies. However, Chinese scholars focus their researches on using idioms as a media to prove their cultural theory while westerners emphasize on their practical function and familiarity in daily usage. Both sides pay little attention on their fundamental formation. Under this circumstance, the research into the effect of culture to language is ignored which makes it possible to use new theory as the intermediary to access new aspect of linguistics.Cultural presupposition is one branch of presupposition theory, which originated from German logistics and become active in linguistics rather than other subjects. Cultural presupposition is not fully exploded in China, thus as a comparatively new theory, it could be used to excavate the basis of language formation. In Chapter3of this thesis, the ideas of the previous scholars about presupposition and cultural presupposition are collected and merged, then blended with the author’s own views of presupposition to form a complete image of this term. Basing on presupposition the veridicality of the hypothesis can thus be proved.This thesis employs cultural presupposition as a basis to study and discuss convention and formation of English idioms.6The order shall be definition and redefinition of culture, the relation of culture and language, theory of cultural presupposition and finally the examples and precise study to illustrate the hypothesis that the creation and spread of English idioms are based on mutual knowledge of people in certain scope, i.e., on cultural presupposition. Based on this fruit, more cultural presupposition interfaces need to be built during language acquisition in or out of class, by which we can achieve best result in lest time; give students the suitable language circumstance; motivate the interaction between teachers and students. Finally the revolution of the quality and efficiency of foreign language teaching can be realized. |