Ronald Dworkin is one of the most influential legal philosophers of the second half of 20th century. He shed light on the modal differences between principle and mile on the one hand and policy on the other. He also elucidated the right to win a case a party has even in a hard case that can be found on the basis of principle rather than policy or of any other discretion judges are supposed to have. He expanded his study to contemporary themes of political philosophy in which Rawls` conception of justice as fairness was largely discussed, and proposed an alternate approach to Rawls`, that is, a conception of liberal equality without original position and reil of ignorance. In this article Dworkin`s conception of know integriry claborated in his book im`s Empire is described and examincd. He finds that law is conceived universally as a hravitational relationship of past political decisions upon the rights of parties to win their cases today, so he assumes that it may well be called a concept of parties to win their cases today, so he assumes that it may well be called a concept a coucept of law. And he analyses three alitudes or couceptions of the concept of law accepted in that wat : Comentionalism, Dworkin`s unique interoretation of Harnan version of legal positivism, is wcak in that it ignores the persistent interests of lawters in the past decisions cven in hard cases. And legal pragmatism, Dworkin`s interpretation of american legal real realism, is not suitable for contemporary legal practices, because it has no reason to rule out so-called checker board rulings, that is, incoherent rules admitting contradictory decisions in a case. He proposes alternative conception of law as integrity, which conceives law, to speak figuratively, as a seamless web, as a totality of decisions with principled consistency and coherence. He sipposes constructive interpretation to weave integral or seamless texture of law, as chain novelists produce a coherent novel. On this theorctial or seamless texture of law, as chain novelists produce a coherent novel. On this theoretical basis, he illuminates several important philosophical and methodogical issues of legal theory, such as finding decision in hard cases, justification of obligation to obey the law and the meaning and role of equality in jurisprudence.