Teacher agency is the intentional choice and action made by teachers to fulfil their personal professional development. The enhancement of teacher agency promotes teachers’ development as well as the curriculum reform. This study selects two young college English teachers as the subjects of the case analysis, who have been guided to learn Production-Oriented Approach and apply it to their teaching practice. The findings reveal that these two young college English teachers display strong teacher agency in the process of applying the theory to practice. And these teachers’ agency is influenced by past experience in the iterational dimension, professional objectives in the projective dimension and school environment in the practical-evaluative dimension. To enhance teacher agency, it is necessary to focus on teachers’ performance at the levels of identification, behavior and adjustment, and help them make appropriate choices and take appropriate actions in teaching.