The notional passive construction (NPC, henceforth) is claimed to be the most common form of passive and the earliest mode of passive expression in Chinese. However, under the view of cognitive construction grammar, NPC remains a mystery with its form not clearly defined and its function not particularly discussed. Taking a character-based historical approach, this paper studies the form designated by NPC, the ‘theme + verbal’ structure in corpus data. Results show that the ‘theme + verbal’ structure is extremely stable in the history of the Chinese language, denoting change of state. In conjunction with some cross-linguistic findings, a change-of-state construction can thereby be proposed for the form ‘theme + verbal’. Accordingly, the idea of the so-called “notional passive construction” is challenged in the way that it essentially refers to a special situation of the change-of-state construction when the event expressed by the verbal is not likely to occur spontaneously- it is not a construction itself, yet plausibly passive.