At the beginning of the article, scientific criterion is presented that serves as the basis for the development of commentary science and also the reasons for it. It is emphasized in the article that the importance of the precise boundary of this particular relationship to the social, humanitarian, natural, or other areas of science, with a specific relation to the history of human civilization. According to this scientific criterion, the origin, formation, and stabilation of commentary science as an independent sobject have been investigated in the post-islamic period. The dissemination of commentary science and the existence of the rules based on any commentary science are founded with the classified evidences. It is adduced that new arguments the scientific methods of commentary science, and its trends have served not only for our contemporary literature, but also for the scientific-literary principles of Western scholars, who were the founders of hermeneutics. The understanding and explanation of the knowledge of Oriental scholars that are typical features of oriental literature are compared with the idealogy of Western scholars based on hermeneutics. The function to explain the meaning of interpretations of classical works is given with proofs.