The “Main Tenet of Nature” Written by Wu-Fong Hu, the third route derived from the Neo-Confucian philosophy, extremely highlighting the “Giving all energy as a second nature”, shall be deemed as a logic premise of the Xiang-Shan Lu, Sect. Hu takes the “Un-Exploitation” as a “Nature”, and the “Developed” as a “Soul”; both are in one when they reach to the ultimate. “Nature” is the heaven as long as the world commonwealth, and “Soul” is the nature as the same as the virtue. Hu’s accomplishments lie in the “Knowledge to give all energy”, or a reverse authentication, together with those methods of the knowledge attainment, investigating the laws, and living with reverences to generalize the relationship between self-cultivations, and further to comprehend the correlation among the subtle strata. In other words, it is Hu’s viewpoint of the “Giving all energy as a second nature”. We shall analyze the implication of the self-cultivation work, so as to understand Hu’s conceptual connotation.