Abstract: The syntactic patterns of comparative sentences in Thirty Kinds of Miscellaneous Dramas of Yuan Dynasty mainly include “X compares Y” and “X compares Y and W”. Such comparative sentences mainly express the equal comparison and contrast. In this work, the auxiliary word “bi” (compare) has not become a preposition and it is in the transition from a verb to a preposition. So it is bound and independent as well. And it has its transitional feature.