The politicization of Confucianism has always been an important dimension to the practice of Confucian realistic values. Strengthening the concept of national identity with Confucianism can maintain the stable order of the country, then realize the enlightenment of social ethics and promote democratic political reform. Yet, Confucianism does not have a specific way to interpret and realize national identity in its cultural connotation. Instead, it shows some meanings of “belonging-identity” in the relationship among individuals, society, and the country. The key point of Confucian “belonging-identity” is its moral nature. We should take the “Supreme goodness” of Confucianism into actualization, socialization, politicization to re-examine and construct an effective mechanism of national identity. Also, Confucianism belongs not only to China. We can apply the Confucian “belonging-identity” system into other Asian countries with similar cultures to realize harmonious relations among individuals, families, and countries. National identity is more a kind of sense, but if we use it in rational political philosophy, such as Confucianism, it can promote the development of democracy of a country.