This study analyzed `Ji(旣)X, You(又)Y` structure in the modern Chinese with syntactic approach and then researched the logical meaning relations between X and Y with semantic approach. Syntactic features may be summarized as follows. First, the subject of X and Y in the `Ji(旣)X, You(又)Y` structure is the same usually, but X and Y each can have different subject in the `Ji(旣)X, You(又)Y` structure in some cases. Second, X and Y in the `Ji(旣)X, You(又)Y` structure all are consisted of an adjective (phrases) and verb (phrases). X and Y can be composed of both the same elements and different elements. Third, each syllabic characters of X and Y are the same or almost similar. However, they can be different when X and Y all are verb phrases of the same elements or different elements. Fourth, `Ji(旣)X, You(又)Y` structure itself can be the constituent parts of a sentence. If they are arranged in order of frequency, most of constituent parts are the predicate. Then comes adnorminal phrase, object, complement, adverbial phrase and subject in that order. Next, meaning relations may be summarized as follows. Basically, logical meaning relations of X and Y in the `Ji(旣)X, You(又)Y` structure are included in combined relations, but they can be classified as three relations such as coordination, sequence and climax. This study reclassifies coordination in this structure as four meaning relations like parallel, mutual dependence and affirmation-denial. Sequence shows X has to happen before Y. Climax means Y`s meaning is more intensified than X`s meaning because of the arrangement of words in increasing order of effect. it can be divided into two kinds of climax such as the concept of natural and reverse direction. To use complex sentences is indispensable in the modern Chinese and the meaning relations between X and Y are the key of vital importance in the complex sentence. Using `Ji(旣)X, You(又)Y` structures can help transmitter communicate with receiver more concisely and compactly. it is better than just to arrange many simple sentences. Furthermore, even though transmitters don`t use typical sequence and climax structures, they can show not only coordination, but also sequence and climax using `Ji(旣)X, You(又)Y` structures. Therefore, transmitter and receiver should all consider logical meanings of X and Y carefully.