Large quantity of researches and discussions connect politeness with social?cultural factors, whereas consequentially cognitive consideration is seldom taken into account. The present study attempts to analyze politeness from the perspective of relevance theory. Politeness is the result of the understanding from relevance theory, which is the combination of the understandings of context, language, communicative intention and culture factors. Compared with previous studies, the relevance theory has a more universal and convincing angel for analyzing politeness.