Arguably, the most contentious debate in the field of eye movement control in reading has centered on whether words are lexically processed serially or in parallel during reading. Chinese is character-based and unspaced, meaning the issue of how lexical processing is operationalized across potentially ambiguous, multicharacter strings is not straightforward. We investigated Chinese readers' processing of frequently occurring multiconstituent units (MCUs), that is, linguistic units composed of more than a single word, that might be represented lexically as a single representation. In Experiment 1, we manipulated the linguistic category of a two-constituent Chinese string (word, MCU, or phrase) and the preview of its second constituent (identical or pseudocharacter) using the boundary paradigm with the boundary located before the two-constituent string. A robust preview effect was obtained when the second constituent, alongside the first, formed a word or MCU, but not a phrase, suggesting that frequently occurring MCUs are lexicalized and processed parafoveally as single units during reading. In Experiment 2, we further manipulated the phrase type of a two-constituent but three-character Chinese string (idiom with a one-character modifier and a two-character noun, or matched phrase) and the preview of the second constituent noun (identity or pseudocharacter). A greater preview effect was obtained for idioms than phrases, indicating that idioms are processed to a greater extent in the parafovea than matched phrases. Together, the results of these two experiments suggest that lexical identification processes in Chinese can be operationalized over linguistic units that are larger than an individual word.