The Buddhist thought of Seng-chao(僧肇) inherited the teaching of Prajña-sutras and the Mādhyamika School in Indian Buddhism, especially the teaching of Nāgārjuna. He accurately understood the concept of emptiness (śūnyatā) that derived from the Mādhyamika School, and further developed his Buddhist thought with more concern on the relationship between the ultimate reality and the phenomenal world. Seng-chao, in his Chao Lun (《肇論》), demonstrated a special concept of the ultimate reality which can be characterized by seven qualities, namely, transcendence, immanence, permanence, dynamism, soteriology, mindlessness and the capability of knowing everything without worldly cognition. On the other hand, NG Yu-kwan established his philosophical system with Pure Vitality(純粹力動) as the core concept. The Pure Vitality is an expression of the ultimate reality with activity (Aktivität) instead of entity as its basic nature. It can synthesize the advantages of the concepts of Absolute Being (absolute Sein, 絕對有) and Absolute Nothingness (absolute Nichts, 絕對無) because it possesses the qualities of transcendence and creativity of the Absolute Being, and immanence and freedom of the Absolute Nothingness. And, at the same time, it can overcome the two concepts’ shortcomings which are the tendencies toward realism and nihilism respectively. The writer is convinced that Seng-chao’s concept of the Saint should be interpreted as an activity which is, in a sense, similar to the basic nature of NG Yu-kwan’s concept of Pure Vitality and this point deserves a comprehensive study.