English set phrases are one of the nightmares confronting Chinese learners. The main check is its ambiguity, in other words, they are apt to varying interpretation. In the paper three questions are discussed: the distinctive features of set phrases, the understanding of ambiguous set phrases and their variants. Under the guidance of Cooper's (1999) heuristic model of L2 idiom comprehension, this paper studies the comprehension strategies of Set Phrases and their variants as well as explores the implications to Set Phrase teaching.
