The Doctrine of the Perfect Teaching is the criterion of Mou Tsung-san's Theory of the Classification of Doctrines. With this Theory he categorizes the doctrines of Confucianism, Taoism and Buddhism. In this Paper we hold that the Doctrine of Perfect Teaching which Mou minds, is based on the Infinitely Intellectual Mind. We have analysed detailly the meanings of the Infinitely Intellectual Mind in following four points: a. The model of the doctrine of perfect teaching in Tiantai Buddhism, b. An interpretation of the meanings of the words ”Perfect” (圓) and ”Teaching” (教), c. the ground of the Perfect Teaching: the Infinitely Intellectual Mind, and d. the importance of the moral subjectivity of human beings for the Perfect Teaching.
