From analyzing the misunderstandings of Max Weber and Jurgen Habermas towards Chinese culture, this essay proposes that the consciousness of rationalizing common knowledge exists in Chinese culture. It looks upon the instinctive sentiments that everybody possesses as naturally rational, and does not trace the causes of the common knowledge of the nature. The primitive form of such mold of thinking was present in pre-Qin Confucianism and Daoism. It then gradually changed to a usual method of thinking during the Wei, Jin, Northern and Southern dynasties, and became the leading principle of ethics as well as the base for constructing the conceptual system in the Sui and Tang dynasties. This essay studies the ideal type of moral philosophy dominated by the rationality of common knowledge, explains why there were only three systems in Song-Ming Neo-Confucianism, and examines how rationality of common knowledge is related to scientism and the economic ethics of modern Chinese ideology. It holds that rationality of common knowledge has made the course of rationalization of Chinese culture different from the West. This is an aspect of utmost importance for comprehending the modern transitions and the future development of Chinese culture.