Chinese idioms have Chinese cultural values. This study aims to find out cultural reflection on Chinese idioms by analyze its syntactic forms. Different from Indonesian language, most of the Chinese idioms (成语 chéngyŭ) consist of four characters. In general, idioms have various forms, such as compounds, phrases, and clause, as well as in Chinese idioms. However, there are several idioms that is difficult to determine its syntactic form or, in other word, syntactically opaque. In addition, we will also examine idioms that are syntactically transparent along with the degree of compositionality of their meaning. Thus, there are two kind of idiom: syntactically transparent and syntactically opaque. Besides, idiom is also related to its metaphorical sense. Metaphorical idioms shows the language user's realm in expressing a situation, an action, or an event which is refer to. To find out whether an idiom consists of metaphor is done by looking at the contribution of the constituent meaning to its whole meaning. The idioms used in this research are a four-character idiom, are taken from the 'Chinese Internet Corpus' online corpus with the highest frequency appearrance. The selected idiom from online corpus will be verified with the 'Xinhua Idiom Dictionary'.Keywords: Chinese idiom, compositionality, syntactic opacity, metaphor