Quantity is a linguistic category about the size, scope and degree of things, events, properties or state of something. And the quantity categories in a language constitute a system. The Chinese one is made of two subsystems: type system and value system. While the value system can be divided into linguistic quantity and substantial quantity in terms with whether the reference of the forms is within or out of the language sign system, the linguistic quantity includes mood quantity and affection quantity. The substantial quantity falls into two subcategories: the basic and the derived, with the latter formed by adding some parameters to the former. And the value system mainly refers to the value, limit, ratio, or order of values. A certain quantity can be defined by its type and value.