As a kind of conversation strategy,backchannelling plays an important role in interaction.This paper discusses the characteristics and roles of backchannellings in cross-cultural communication in ELF.With the help of conversation analysis,the author studies Chinese and foreign students' conversation in class in University of Shanghai for Science and Technology and finds that 1) the frequency of non-lexical backchannellings is highest,while the frequency of phrasal backchannellings is the least;2) the uses of competitive backchannellings are far less than cooperative backchannellings;3) both Chinese and foreign students tend to use more backchannellings with non-native interlocutors;4) the frequency of using backchannelling in foreign students is higher than in Chinese counterparts.This investigation may provide some references for further study of ELF conversations.