Foreign language learning has distinct characteristics different from knowledge learning in other disciplines, especially focusing on the creation of language environment, emphasizing students' interactive participation and being highly practical. With the rapid development of multimedia computer and network education, constructivism theory shows its strong vitality and its influence is expanding in the world. What kind of teaching mode to construct, how to embody learners' subjectivity in teaching, and the relationship between teachers and students in the modern network environment need to be discussed by foreign language teachers. This paper discusses the combination of constructivism theory and multimedia network English Teaching in the network environment, so as to find out the teaching mode suitable for English Teaching in China. The change of teachers' role is from "housekeeper" in traditional teaching to "sheep herder" in network teaching. This role transformation fully reflects the learning law of constructivist learning theory. After continuous research and practice, it has achieved great success.