Abstract: Based on the Educational Ecology Theory, college English classroom is a micro-ecological environment with the characteristic of equality, harmony and openness. Teachers, students and the classroom environment are the three prominent ecological factors. It is only after these three ecological factors have formed a kind of dynamic balance that college English classroom teaching can be optimized. Therefore, this article will conduct a study on teachers' role in college English classroom teaching, exploring the ecological roles of college English teachers so as to create ecological classroom and achieve sustainable development in college English teaching.