The purpose of this research is to develop and motivate a theory of passive constructions under Minimalism. This theory includes three proposals: firstly, accusative Case is available in passives; secondly, nominative Case takes priority over accusative; finally, a Passive Phrase exists between TP/VP and vP. English passives and Chinese bei-constructions are analyzed based on the Agree and Phase system in Chomsky’s recent framework, Minimalist Inquiries. In conclusion, a unitary syntactic structure and derivational process of English passives and Chinese bei-constructions are developed. The passive functional category is phonologically covert in English while overtly realized as bei in Chinese. They both head a strong Phase and have an EPP-feature and a specifier. They also have the same selectional properties: they can be selected by T or V and take a vP without a specifier as their complement.