The construction of metaphysics system is the main work of Tang Jun-Yi as a great master of Neo-Confucianism, and the metaphysics is a keystone of his philosophy. Therefore, it is of great significance to reveal the construction course of metaphysics from Moral Self to Mind Realm, which focus on the basic idea of taking mind as noumenon, and the profound meaning of his metaphysics system. By doing so we can not only understand his philosophy holistically and intensively, but also apprehend its creative ideas and the shortcomings. Moreover, we try to match the research of Tang Jun-Yi's philosophy to his academic authority status in contemporary Chinese philosophy.We employ the unification of logic and history as our principal method in our research. We illustrate respectively the three phases of the construction course of his metaphysics system from both points of view of logic and history in the first three chapters. We then examine and reflect on his metaphysics wholly with comment on its excellences and weakness in the last chapter.In the first chapter, we comment on the construction course of Moral Self as the essential notion. Firstly, we pursue the transformation and orientation of philosophy notion of Tang Jun-Yi in his youth. Then we discuss the start and foundation of Moral Self, demonstrate the existence of the noumenon of mind, and indicate the route of Moral Self to improve itself. At last, we analyse the traditional source used in the construction of Moral Self.In the second chapter, we illustrate the process of Moral Self objectifies itself into culture world. The notion of Moral Self with characteristics of subject constructed in the first phase outspreads itself in the second phase of his metaphysics system, withthe result that brings out various forms of culture as philosophy, science, literature and art, religion and morality, family culture, economy, politics, physical education, law, education, and so on.In the third chapter, the notion of Moral Self realizes itself into all the activities of Human Being. We expound the activities of Human Being in the third phase of the metaphysics system that include three directions and consist of nine realms. And then comment on the essential meaning of these nine realms.The last chapter brings forth our comment on the metaphysics of Tang Jun-Yi holistically. In the first instance, we sum up the metaphysics notion of Tang Jun-Yi and the character of dialectical development in his metaphysics, review on his metaphysics system in the context of history of philosophy. Then we reveal that his metaphysics is tied in with his epistemology, the dimensionality of Mind transforms in the different phases. Lastly, we show he how to inherit and overstep the philosophy tradition of both western and eastern in his metaphysics system and emphasis the importance of his metaphysics.