This study investigates washback effects of IELTS test on university teachers' adoption of teaching materials in the classroom in China and see how a high-stake language exam affects their teaching practices and how they and their students perceive the effectiveness of the pedagogic adjustments. To this end, individual interview to five teacher participants was carried out and a questionnaire was administered to over 100 students. The results show a positive washback effect as, influenced by IETLS test and students' needs to achieve high scores in IELTS test, teachers sought to focus more on IELTS-related content in the textbooks and adopt extra IELTS-related teaching materials to help improve students' test performance. Also, students recognized teachers' arrangements on class practices and believed such practices were useful in enhancing their IELTS scores. Moreover, teachers' choices and modifications of teaching materials were not determined by washback effects of IELTS tests only but rather a result of coaction between various factors including the state's educational policies, personal research areas, teaching rationale and abilities to modify teaching materials.