Abstract:Doctrines of Qi, Li, or Mind as noumenon are most prominent systems of Neo-Confucianism in Song and Ming dynasties, whereas a doctrine of Tao as noumenon Doctrines of Qi, Li, and Mind as noumenon were most prominent the ideological systems of Neo-Confucianism in Song and Ming dynasties, whereas a doctrine of Tao as noumenon was the typical form of philosophical metaphysics in Qianlong and Jiaqing times. For the ideological systems of that time, Tao was the most significant concept which integrated Li, Qi, Mind, and all other central concepts used by the Neo-Confucians; it was a truth in human cognition, and also an ideal value beyond all disciplines and techniques. Dai Zhen, Zhang Xuecheng and Qian Daxin were eminent in the doctrine of Tao. They rejected the speculative tradition of Neo-Confucianism, and laid emphasis on “searching Tao through the transformation of Qi”, “illuminating Tao by corporeal matters”, and “searching Li by visible things”, and gradually stepped on a way of empiricist and positivist approach to Tao, which reflected a great change in the deep ground of Chinese philosophy.