Metadiscourse is the language which can indicate the structure of discourse,call for the attention of readers and reveal the attitudes of writers in texts.In light of the functions of metadiscourse,based on the classification of English metadiscourse made by Hyland Tse(2004),this paper illustrates that the use of metadiscoure can avoid speaker-centered talk,help to fuifill the task of communication and construct interpersonal relationship.