Xunzi was a renowned leading scholar following in the footsteps of Mencius in the Warring States period. While Xunzi’s Confucian teaching took a central focus that all people were evil, and emphasized an etiquette and morality-led doctrine that mainly featured a predominant focus on accumulating study and following later kings’ teaching. Nevertheless, among Xunzi’s teachings, a significant concept of his that set it apart from the aforesaid characteristics but served essentially to integrate his practical theory, moral doctrine and humanistic ideology had been the “categorization/class”, which is containing the abundant philosophic theory, so that should be paid attention to and probing into by more scholars. In light of which, the thesis has attempted to interpret its main significance in philosophy through analyzing and interpreting the meaning of “categorization”, and to explore methods of knowing the “intergration of categorization統類”. Upon undergoing a theoretic study premise primarily adopting literature analysis and interpretation, the thesis has initially discerned and recapped the philosophical significance of the phrase “categorization” other than its common usages, meaning that in Xunzi’s teachings, the phrase “categorization” has three distinct meanings of,（1）logical doctrine in the sense of knowledge acquiring theory;（2）the cultural doctrine in the sense of morality; and（3）the legal doctrine in the sense of the science of the law. And the preeminent criterion in what Xunzi’s had criticized of the assertion, people and things of ignorance and inability to understand the “intergration of categorization統類”, or achieving an adaptable ideal character through reduction reasoning lies in how one needs to possess an undivided, humble clear mind, before one is able to perfect oneself through accumulated learning and disciplinary training.