Language teaching is both a communicative and cognitive process. College English class teaching is essentially a communicative interaction between teachers and students. Based on communication and cognition，Relevance Theory，with its concepts of communicative view，cognitive context and Relevance，has an effective guidance for college English class teaching. College English classroom teaching is essentially，based on cognition，with the purpose of communication，to pursue the optimal relevance of the information in mutual cognitive context. Example analyses of college English classroom teaching show that the teaching design and innovation should be carried out from the relationship between teaching content and students’ cognitive context.