This paper proposes a syntactic account for the licensing conditions and interpretations of indefinite subjects in Mandarin Chinese. Three dimensions are explored: subject specificity, predicate distributivity, and scope interpretation. We suggest that the indefinite subject be best treated as a variable, which has to be bound by certain operator, to account for its various readings. The property of its corresponding operator in turn determines the specificity of the indefinite subject: The specific/presuppositional reading is licensed by the existential predicate you 'have/exist' serving as an existential quantifier YOU, while the nonspecific/ cardinal reading is licensed by either the implicit existential closure (Diesing 1992) at Mod' (Tsai 2001) or you serving as the overt realization of the existential closure. Furthermore, the predicate distributivity plays a nontrivial role in licensing indefinite subjects. I propose a hierarchical account to clarify the two confusing notions, i.e. specificity and distributivity, on the interpretation of indefinite subjects. The distributive reading of indefinite subjects is licensed at a higher position than the collective reading. Finally, the wide-scope indefinite phenomenon is attributed to the scope-independent reading (Liu 1997) which in turn is licensed by specificity and distributivity. In a word, each of the three dimensions mentioned above contributes to the interpretation of the indefinite subject in Mandarin Chinese.