English Listening is one of the basic compulsory courses for English majors in China.Vocabulary,as an elementary factor in language and acquisition,is the foundation of learner's listening comprehension and speech production.Supported by Kahneman's attention theory and second vocabulary processing theory,this paper discusses the lexical representations of selective attention in computer-assisted Listening class.It proposes that perceptual load,cue location and stimulus-driven determinants are the key factors which influence the selection of attention.At the level of utterance perception and recognition,selective attention focuses on learner's knowledge of pronunciation,rhythm and word recognition.While at the level of semantic processing,selective attention focuses on learner's recognition and understanding of linguistic features and cultural background of western cultures as well.