Abstract: As one of the founders of Song Ming Neo-Confucianism, Zhang Zai emphasizes qi (“气”, usually translated as material force) to form his philosophy is original and contributory to explore the interconnectedness between the universe and humans. However, it has also been debatable since proposed. To sum up, three interpretations for Zhang Zai’s philosophy of qi competed with each other: the uniqueness of materialistic qi, the duality of li-qi (li, “理”, usually translated as the principle or pattern), and the uniqueness of transcendent qi. This paper aims to comprehensively examine these three interpretations by comparing their validity in textual reading and philosophical thinking. It also argues that considering Zhang’s qi as transcendent is the most appropriate interpretation, carrying particular implications to Confucian philosophy in terms of metaphysics and cosmology, the theory of human nature and heart/mind, and the ways of making virtuous efforts.