Process of democratization promoted the development and improvement of American Social system. The protection of American historic buildings was involved in this process. The protection of American historic buildings was originally launched from the public level

and developed into the representative NGO organization

the?National?Trust?for?Historic?Preservation (NTHP) . Its establishment combined the protection power from the state and the people

and had become an important factor to promote the national legal construction and public participation. In this way

the U.S. gradually formed the heritage protection mechanism from the regional aspects such as the typical Historical Society of New England and Bacon Hill Citizens' Association

Boston which promote the development of the protection of American historic buildings . Study on the U.S. formation process

social characters

historical function and organization form of these historic buildings protection organizations can provide experience for the establishment of public participation mechanism in our country.