Context in the use of irony refers to the subjective factors of verbal communicators and the objective factors of the applying environment. It can usually play the roles of hint and restriction. The use of irony involves the metonymy of mutual transfer between parts to whole. The reason why utterance p can refer to utterance -p lies in the fact that the former is more prominent than the latter. The reason why the source domain can activate the target domain and provide mental access to it is based on the contiguity between the two conceptual objects. Utterances p and-p share opposite-directional proximity in semantics. The fact that speakers use irony instead of speaking directly has something to do with speakers＇ intentions. Conceptual metonymy is the mental way that must be taken by irony in the course of its meaning transfer.