Communicative approach attaches importance to teacher-student relationship and teacher-student interaction,holding that teaching is first of all a process of interaction.But EFL teachers may pay too much attention to classroom communication fluency,while overlooking students' language accuracy.Or information gap is absent from interaction and students may be reduced to merely an object of interaction.So this paper tries to analyze how computer-and classroom-based multimedia College English teaching model takes advantage of instructional interaction in the perspectives of students' talk,manifolds of interaction,frequency and depth of interaction and students' social and affective strategies.