The primary aim of Jeong Do-jeon’s criticism of Buddhism is, like Mencius, to promote both political and moral actions based on the virtues of Confucianism. In a similar way to Mencius’ denouncement of heretical discourses, Jeong Do-jeon thinks that the disapproval of Buddhism is indispensable for accomplishing the ways of Sages-that is, for effectuating the virtues of Confucianism. Rather than an intellectual debate against Buddhism, Jeong Do-jeon’s criticism of Buddhism is done in the context of political movement, to incorporate Neo-Confucianism as a national ideology. His disapproval, followed and enhanced the discourses of former Confucianists - Zhang Zai, Cheng Brothers, and Zhu Xi - displays both distinctive criticism of Buddhism and better understanding of Neo-Confucianism than other relevant Neo-Confucianists of the Joseon Dynasty. In his book Bulsi-japbyeon 佛氏雜辨, Jeong underlines that Neo-Confucianism, which is based on the concrete facts unlike Buddhism, has realistic practicality, and maintains that the ontological foundation of human morality exists by showing the distinction between the nature(性) and the mind(心). Jeong’s argument has two implications: first, it sheds light on the living moral agent even in fluctuating political conditions; second, it shows that Jeong did not simply reiterate Zhu Xi’s criticism of Buddhism but, based on his particular systematic understanding of overall aspects of Neo-Confucianism, Jeong did criticize Buddhism in his own way. From this point of view, it could be understood that Jeong Do-jeon’s disapproval of Buddhism focuses on the realistic value of the virtues of Confucianism and its actual practice, unlike his predecessors of the Song dynasty who focused on human nature, mind and self-cultivation.