The theory of ＂Heart as Noumenon＂ is the most important philosophic foundation of Tang Junyi＇ s aesthetics, which refers to human beings ＇ spiritual activities as the ＂noumenon＂ while the various cultural ideas are the use of the ＂noumenon＂. Tang Junyi thinks that the significance of lives lies in the pursuit of the aesthetic activities of our spirit, and seeking the beauty of nature and literature and personality isn＇ t only the rising course of spiritual self-transcendence, but also the important approach to moral self-improvement. What＇ s more, he also analyzes the nature of beauty, the spirit of Chinese arts, the characteristics and the causes of Chinese tragedy.