I studied Dewey's moral philosophy dividing into four categories such as the theory of value, the theory of conduct, the theory of morality and the theory of education. First, from the theory of conduct point of view, the conduct was formed based on the achievement of biology, psychology, and sociology. In biology, he established habit and impulse which are biological elements as a motive power which functions basically on the action. In Psychology, human action is defined by a concepts such as love, creativity, self-fulfillment and mental health etc. And in sociology, the action is formed through reciprocal actions between natural circumstances and social circumstances. Second, in the theory of value, he understood that the value judgement and practical judgment were same. The thought this judgement was the one that needs action. He sorted out these characteristics of practical judgement as three categories. He mentioned that the aim and means are inseparably related to each other by distinguishing the original value from the implemental value. He thought that if the value judgement and practical judgement which were proved scientifically were turned to be identified, the knowledgeable basis of ethics would be realized. But he knew that the possibility of the above was slim. Third, in the theory of morality, he pointed out the vice of the traditional morality and he made clear that the basic task of ethics is to pursue the virtue and execute it. Moral virtue is supported and developed through mature consideration. Morality is closely related with estrangement. Therefore, in this respect, we can conclude that morality is social. so the basis of morality exists as humanity and sociality. Fourth, the theory of education. Dewey considered the theory from three points of view such as experience, growth and democracy. When we see the education on basis of experience, there are the character of continuation and the theory of reciprocal action. These two theories can't be separated. The Growth has two characteristics such as the character of dependence and plasticity. And democracy adopted the freedom and equality as a basic idea. The education of democratic society is achieved through understanding based on the above concept. In conclusion, I would like to finish this thesis making clear that I criticize the defect of his moral philosophy. In addition to that, I clarify his merits by studying and analyzing his thought.