The thesis discusses the theory on the integration of Confucianism and Buddhism constructed by Mou Tsung-san. From the process of constructing the duplex ontology, Mou Tsung-san greatly integrated Confucianism and Buddhism in theory.Firstly, the thesis explains the disability of the integration of Confucianism and Buddhism brought by Lao Sze-kwang for the difference of the value consciousness toward this shore and that shore. Lao Sze-kwang also argued that a higher language system cannot be built to control the theory of the two parties. Therefore, the integration can only be applied in life.In the second section, Yeh hai-yen thinks Ven. Yin-shun of Humanistic Buddhism advocates the integration of Confucianism and Buddhism within the meaning of human morality. However, the author thinks that this meaning of human morality is not sufficient nor bases on breaking through Lao's theory.As a result, in the third and forth section, it indicates that Mou had indeed constructed a philosophic system and used a higher language system to contain the ontology of Confucianism and Buddhism. Within the system, there are four points: "Infinite mind", "Two-gate-in-one-mind", "Intellectual intuition" and "Non-analytic approach". They all indicate Mou's duplex ontology. Mou confirmed the Attached and Non-attached ontology. The Attached ontology means confirming the value of this shore. It matches Ven. Yin-shun's confirmation of the human morality of this shore and breaks through Lao's argument. It does not hinder the integration of the twos under the Mou's system, even if there exists differences between the Confucianism and Buddhism.Finally, the author affirms the academic achievement of Mou. His theory has been presented in front of us. No matter it is accepted, people still should open their mind to accept any opportunity of the integration of world culture. After all, from the establishment of Buddhism, this shore has actually existed. In the thinking of the coexistence of both shores, the idea of abandoning this shore to accomplish that shore has been more harmonious.