Lexical distribution in the language system is not in a heap of loose sand, Lexical as a kind of system that is a subsystem of the whole language system. The Modern Chinese Lexical system is composed of words and the fixed structure of words. The fixed structure comprises idioms, phrase, proverbs, Xiehouyu and proper nouns, they are stereotype structures, independent sentences, and have the same functional properties with the words, so fixed structure and words are the two basic elements and in the same line of the Lexical system. This thesis attempts to analysis the elements in the Lexical system through synchronic perspective to show that the lexical system is composed of a relationship, and this relationship is formed by all components of the Lexical system according to their own characteristics and a certain order. There are three main types of this relationship, hierarchy relations and syntagmatic relations and paradigmatic relations. In brief, The hierarchy relations is the hierarchy and level of words in the Lexical system. Syntagmatic relations refers to the combination ability between word and word. Paradigmatic relations means the components in the lexical system is always combined with the same or similar, or even contrary meaning of the other components to form various similar clustering relations. From this thesis we can see that the modern Chinese Lexical system formed the overall appearance and linked to each other through hierarchy relations and syntagmatic relations and paradigmatic relations.