Among his numerous writings, Ethics is one of Peter Kun Yu Woo's best sellers in Taiwan, publishing more than twenty editions. He was profoundly influenced by traditional scholastic education, emphasizing the importance of ethics as practical philosophy, and convinced that ethics is the knowledge of how to be a man. With five hundred and twenty-seven pages in total, Ethics is divided into three sections-the historical development, the internal immanence and the contemporary meaning- based on the tripartite style characteristic of the writings during the middle and late period of his life. Regarding the fundamental position of ethics, the writer inducts the six points as follows: only the ＂internal and intellectual behaviors＂ is the object of ethics; the meanings of good and evil are assumed to involve intellect and virtues; conscience is one of the subjective standards of morality, but not the only one; conscience involves autonomy and heteronomy; the liberty of will is assumed; the distinctions between all the schools and sects are based on the subject and object of morality. Regarding the features of ethics, Woo's ethics is constructed out of criticism and reflected in the following four points: ＂practice is re-affirmed to be the first meaning of ethics, opposing to distinguishing between meta-ethics and normative ethics as ＂is＂ and ＂ought;＂ emphasizing the family culture as the foundation of special ethics; and pointing out the faults with deontology. From Woo's framework of ethics, we can conclude that the virtue ethics is the foundation of ethics, while admitting that ethics itself is insufficient, it must resorts to the foundation of metaphysics and the insufficiency of ethics should be supplemented by religion.