Politeness is the badge of human civilization,and a significant criterion to human society activity; politeness,as a social phenomenon,is the imperative tool and method to maintain human relation in perfect harmony; politeness is a kind of social conventions,it lays certain restraints on all the social members. From ancient to modern times,either in East or West,people always attach great importance to politeness. To save face of the speaker or the hearer,politeness is of considerable practical significance in the conversation. As a matter of fact,its value can never be underestimated. However,due to different historical,lingual and cultural backgrounds,different societies may have different criteria to politeness. And this leads to some problems such as misunderstandings and embarrassments in cross-cultural or intercultural communication. In order to solve these problems,many scholars and linguists at home and abroad have proposed different principles of politeness so far. The author aims to make a comparative study on politeness principles between Chinese and English language and cultures. Analyzing the differences can help to remove the communicative barrier encountered by people who come from different countries with different cultural backgrounds and effectively promote further mutual understanding and cross-cultural communication.