Abstract
"thank you" is the most frequently used language of thanks in modern Chinese, which is often used to implement the speech act of thanks. It is not only a polite expression, but also involves more complex language functions and social significance. Starting from the speech act theory, this study examines the types of the speech act of "thank you". The results show that in Chinese, "thank you" mainly shows several speech act types, such as gratitude, rejection, politeness and so on. With the help of the analysis of corpus data, the study also shows the frequency of "thank you" in different contexts, and it is concluded that "thank you" is used to express gratitude most frequently, followed by refusal, politeness, mantra, irony, expulsion, order, reminder, and finally warning and threat. On the one hand, this study provides empirical support for understanding the speech act of "thank you". On the other hand, it can also provide reference for cross-cultural communication and language teaching.