This study, based on the conceptual contrastive model for Chinese and English idioms, examines the effects of Chinese concept transfer on comprehending English idioms by advanced Chinese EFL learners. A questionnaire survey was conducted to explore their strategies for comprehending different idioms as well as the language transfer that occurred. The results show that: 1) Chinese concepts significantly influence learners’ comprehension of English idioms. Positive transfer occurs when learners comprehend the English idioms which have the same concept and the same or similar linguistic forms in Chinese, while both negative transfer and positive transfer might occur when learners comprehend English idioms of the same concepts but different linguistic forms. Negative transfer occurs when learners understand idioms of different concepts, no matter whether their linguistic forms are the same, similar or different. 2) When understanding idioms of the same or similar linguistic forms in Chinese, learners do not directly adopt the strategy of “borrowing Chinese”. When understanding idioms that have both Chinese different linguistic forms and concepts, learners tend to resort to Chinese language. Learners should learn English idioms by means of Chinese and English concepts. In addition, understanding the rules of idiom transfer can help L2 learners avoid the negative influence of their native language.