Abstract: The multiple meanings of Rang in modern Chinese have been one of the main concerns among scholars. Two functions of Rang,that is,verb function and prepositional function,have been identified in the literature. Within this traditional approach,many practical problems concerning the usage of Rang have been left unsolved. This paper explores the meaning and syntactic functions of Rang from the Cardiff Grammar perspective,a model of Systemic Functional Grammar. The study shows that there are three functions of Rang in modern Chinese: verb function,prepositional function and “Let” element function.When Rang is used as a verb,it expounds the Predicator of a clause,which realizes process meaning;the causative usage of Rang should also be treated as a verb rather than a preposition. When it is used as a preposition,the function of Rang is to introduce the Agent of the process,which together with the following nominal group should expound the clause element of Complement rather than Adjunct syntactically. When it is used as “Let” element of a clause,it is only a mood marker,which has no experiential meaning.