When English becomes the international language with the globalization of the world, it is not surprising that EFL teachers are pushed to the front of TEFL (Teaching English as a Foreign Language) because teacher quality is thought to be the factor that matters most for student learning. EFL teachers are expected to be more knowledgeable and competent. So their in-service professional development seems to be indispensable to help them reach higher professionalism. This study aimed at investigating the activities and effectiveness of the workshop that is an important element of the Multilayered Peer Coaching Model (the MPC Model) developed for tertiary EFL teachers’ in-service professional development. Twelve EFL teachers from Guiyang University in China participated in this study, and such instruments as observation, teachers’ log and interview were employed for data collection. The results showed that this workshop was effective and could smoothly lead the participants to the follow-up teaching practice which is another critical element of the MPC Model.