All the works including sculpture created by modern artists contain a message that represents both the ideas and spirit of an era. We are entrusted with the responsibility of transmitting to future generations modern art in as nearly as perfect condition as possible. Thus despite the challenges we face in preserving modern art, we are obliged to conserve it. Especially, outdoor sculpture can be considered as not only works of art themselves, but also a public art. The work of contemporary sculptors often refers to the complexity of social relationships between the art and the public space, so that the public space tends to include the actual public in the art. The conservator at this point needs to preserve tile concept of the public art which is incorporated in the public participation in the sculpture, in addition to the materials of the sculpture itself. Once the sculpture is damaged, it will need restoration. Restoration may be essential to prevent further deterioration, or it may be necessary in order to make an object usable again. It is difficult to generalize about restoration because, as with preventive treatment, the acceptable degree of intervention varies from one discipline to another The degree of treatment including restoration may depend on such variables as available resources, the future use of the object, and the needs of the particular discipline to which it belongs. When conservators start to treat artworks or during the treatment, they will face many moments where they have to make a choice. Codes of ethics are necessary in order to provide a basis for making choices. Even though ethics have always been subject to change depending on an era or culture, the ethics subject will be much easier to reached an agreement on than one involving aesthetic value. The aesthetic value will be one of the most prominent factors for defining the damage: even minor loss of parts or discolouration can be considered as fatal damage for artworks. Sometimes, an alteration of the appearancecould be intended by the artist himself so that the artist's intention could be important factor for judging the damage of artworks. But, modern hermeneutic theories show that the artist's intention cannot be the only factor for consideration, so that the interpretation and application of artist's intent should be an interdisciplinary task regarding distinctive social and cultural backgrounds.