Phrasal expressions can be a rich source of cultural information, so lexical treatment of idioms has long remained a hard work for bilingual dictionary compilers, Traditionally,they would watch their monolingual dictionary colleagues' steps in collecting and defining items, which can hardly satisfy the demand of second language learners and translators. This dissertation is meant to illustrate, with the latest development of phraseology, the significance of stylistic demonstration of idioms incognitive, pragmatic, and bilingual dictionaries.