Abstract: With the economic globalization and China's accession to the World Trade Organization, the communication between Chinese and Westerners is more and more frequent. Politeness, as the major standard of the communication, is very important. In cross-cultural communication, people who are from different cultural backgrounds and speak different languages often encounter the cultural differences. Therefore, learning the differences in politeness speech acts and avoiding misunderstanding mean a lot to a successful cross-cultural communication. The thesis is composed by five parts. The first part introduces the background and significance. The next three parts is the main body. The second part gives a brief introduction to the politeness related theories in home and abroad. The third part has a concrete analysis of the differences in politeness speech acts between Chinese and English. And the fourth part suggests some ways of avoiding pragmatic mistakes in cross-cultural communication. The last part is the conclusion. By the analysis, the thesis means to improve the awareness of the differences in politeness speech acts and promote successful cross-cultural communication. 

Keywords: politeness principles; cross-cultural communication; differences; pragmatic mistakes