This study investigated the teaching of academic English in Xi'an Jiaotong-Liverpool University to explore the impact of its model of developing speaking and writing skills on students' academic study. The university offers a two-year compulsory courses of English for academic purposes (EAP) for students and chooses English as the working language in all the academic courses. The survey involves some students of four grades and teachers of different academic courses in questionnaires and interviews. Feedback from the participants revealed that students' more speaking and writing practice in the EAP classroom significantly improved their skills in speaking and academic writing, as well as critical thinking，so do their comprehensive study skills. Based on the findings from students' full English course learning, The author proposed some suggestions for teaching EAP.