H.G.Gadamer carries forward the great tradition of the Western practical philosophy in his philosophical hermeneutics, which has a close relation with ethics. This relation runs through Gadamer’s whole academic career, especially in his later time. It is quite natural for him to turn to the value ethics from understanding ontology. The link between both of them is the hermeneutic dialogue and his basic ideas, such as “the relationship of I Thou”, “fusion of horizon”, etc., which are reflected in the dialogue. What makes later Gadamer come to ethical practical philosophy are the tradition of Western practical philosophy and the difficult position which mankind has encountered nowadays. He restates the fundamental status of practical reason by reflecting the reason itself and stands out its sociality, as well as the important content of the social reason which mainly includes human being’s solidarity, identity and friendship. There are two main sources of his practical philosophy: one is Platonic Aristotelian idea of good, the other is Hegel’s dialectics emphasizing “reconciliation”. It is endued with a new implication and a sharp modern sense when they are put into the context of the doctrines of Husserl’s “life world” and Heidegger’s “hermeneutics of facticity”, based on which Gadamer develops his own practical philosophy. It is a dialogue ethics, which connects with politics. The dialogue community that he advocates can be regarded as a language Utopia. Its ethical meaning is more profound and more extensive although it refers to the polis of ancient Greece. It leads to a pacifism of the world at last.