This paper addresses the issue of Bei Constructions as passive constructions in Mandarin Chinese within the theoretical framework of Dynamic Syntax (Kempson et al.2001). On the basis of a detailed examination of the basic facts about Bei Constructions, it is claimed that (i) the morpheme Bei is actually a voice particle devoid of any semantic content, precisely an indicator of the inverse direction of action; it is by virtue of this peculiar function that Bei is generally regarded as marker of passives and Bei sentences are universally considered as passives in Chinese; (ii) from the typological perspective, the voice behaviour in Chinese is a type of pragmatic voice; from the functional perspective, Bei Constructions share certain similarities with topic constructions and thus can be treated as a species of left dislocation. Under the dynamic approach, various patterns of Bei Constructions have been successfully characterised in an original and elegant way.