Since 2007, the Ministry of Education of China has been promoting a shift from traditional teaching models to a new teaching model where students' autonomous learning skills can be enhanced. In particular, college students are encouraged to learn English free from the constraints of time or place. While learner autonomy has been perceived as contributing tremendously to student learning, it is a new concept to many local teachers and students. Many teachers even think that the emphasis on learner autonomy means teachers' functions are on the decline. This paper reports on an empirical study that investigated the current roles that teachers play in the context of learner autonomy. Through a questionnaire, the study reveals that teachers took on more challenging and multiple roles in the new teaching model. Meanwhile, the structural model for teachers' roles has been built so as to give implications to college English teachers in China.