Objective:To investigate the model,quality as well as effect of teaching-in-English in five-year clinical medicine program of Hainan Medical University.Methods:The questionnaire was carried out among clinical medicine undergraduates of 2012-2015 grades in Hainan Medical University,to investigate studying time,studying habits and the impact of teaching in English.Additionally results of CET-4,CET-6 and overseas intship from undergraduates of 2012-2015 grade,as well as the result of phased medical licensing examination and post-graduate entrance examination from undergraduates of 2012 were accordingly collected from the Teaching Management Department.Results:For the Chinese students in intational classes,the average time of self-study was 161.49 min,58.3％ had preview before classes,and 90.7％ had habit of review after classes.Thus the first time pass rate,total pass rate,first time excellent rate and total excellent rate of CET-4 and CET-6 of intational classes were significantly higher than those of regular classes.The result of post-graduate entrance examination in 2016 showed that the score,pass rate and acceptance rate of intational classes of 2012 grade were significantly higher those of regular classes (P ＜ 0.01).Conclusions:Teaching-in-English reform in Hainan Medical University has achieved initial success.Chinese students from intational classes are superior to those from regular classes in many aspects.However,there are still many problems,and effective measures should be implemented to promote teaching quality continuously.