Philosophy can be divided into two systems, i.e. the vertical and the horizontal. Characterized with the creation of spirit and the logical evolution of concepts, the vertical system expresses historical reflections on the achievements of human culture. Meanwhile, the horizontal system focuses on the analysis of cognitive activities to explore the nature of subject and object, the elements of knowledge, and the basis of its certainty. Chinese philosophers, such as Hu Shih, Fung Yulan, Zhang Dainian, Mou Zongsan and Zhang Shiying, have previously explored the various definitions of philosophy. Their explorations manifest the internationalization of Chinese philosophy during different eras. This paper defines philosophy as human beings’ awareness of their environment and systematical reflections on their activities and ensuing consequences. As part of world philosophy, Chinese philosophy encapsulates the essence of Chinese culture, as the thinking method of Chinese people, and as a set of thought systems possessing a unique style.