In this paper,we discuss four kinds of weighing-level modes of coordinate complex sentences in the Middle Ages:asymmetric,weakly symmetric,symmetric and strongly symmetric.In the Middle Ages,coordinate complex sentences have the characteristics of rich types,outstand-ing advantages and overall U-shaped distribution,while showing obvious textual differences,stylis-tic differences and stage differences.Compared with ancient times,the symmetry of coordinate complex sentences in the Middle Ages increased,and the symmetry and symmetry of coordinate complex sentences were actually driven by the characteristics of Chinese,people's cognitive style and the function of language.