In the past, researchers often referred to "utility" to criticize Zhu Xi and other Confucians' political discussion of "inner holiness and outward governance", arguing that such a point of view is impractical. This article attempts to point out that the reason why Zhu Xi reinterpreted the political discourse of "root and branch all-pervading unity" based on "The Great Learning" was to challenge the "double world view" of Buddhism and Taoism during the Song Dynasty, and to take back the discourse-dominance of the political and religious order from Buddhism and Taoism. Therefore, we may understand that Zhu Xi was devoted to constructing a new political discourse system "keyword" by deliberately emphasizing the four characters of "誠意正心" (rectify their hearts and seek to be sincere in their thoughts). In addition, although Zhu Xi's political discourse on "root and branch all-pervading unity" based on the "Great Learning" emphasizes that "the root should not be neglected", meaning that the foundations and fundamentals should be cultivated, he also affirmed that "the branch should not be neglected". In fact, Zhu Xi did not ignore the issue of "practicality". In particular, by observing Zhu Xi's criticism of the chaotic judicial order in the Song Dynasty, we can see that he attached importance to the "virtue and propriety" which were at the "root" of the Confucian tradition of moral governance since the time of Confucius. However, because he observed that the Song Dynasty was deeply rooted in Buddhism under the influence of the concept of reincarnation, judicial decisions had an issue of "light sentencing." Therefore Zhu Xi also emphasized "laws and punishments" where the "branch" shouldn't be neglected.