This article is about how Tang Jun-yi compared Zhu Xi's and Wang Yang-ming's theories, making his best efforts to subvert the traditional view that Cheng and Zhu belonged to one school of Neo-Confucianism while Lu and Wang belonged to another. Tang pointed out that sometimes Zhu was similar to Wang and different from Lu, as Lu's idea of will determination was distinct from Zhu and Wang's theory about ＂reducing human desires to preserve heavenly principles.＂ Furthermore, Tang disapproved some of Wang's criticisms about Zhu and defended his idea about the distinction between mind and principle, while celebrating Wang's ideas of ＂knowledge as action＂ and ＂fulfilling the innate knowledge＂ were superior to Zhu's ideas of ＂knowledge before action,＂ ＂the eight steps of cultivation＂ and the ＂division between essence and practice.＂ However, the writer believes that Tang neglected that fact that a great part of Zhu's theories was commentaries and not supposed to surpass the original meanings of the texts. On the other hand, Wang was making philosophical creation and therefore enjoyed much more freedom. It is not right to comment on the merits and weaknesses between Zhu, Lu and Wang without paying attention to the differences between commentary and creation or the fundamental differences and similarities in their philosophy. Even so, concluding Tang's discussion, the writer still believes that Mr. Tang was the best reviewer of Zhu's and Wang's theories and should be advocated.