Abstract: As a means of urban greening, the building of roof garden, along with urban renewal movement, is an important measure for city renovation in America. At present urban renewal is in progress in many cities of our country, and the use of various technologies and measures in urban renewal has been paid more and more attention. The paper studies the application of roof gardens in America for solving problems appearing in urban renewal, analyzes the ways that roof gardens have been applied in urban renewal with outstanding cases of various types, and sorts out the development of roof gardens. This paper is expected to offer some references for the urban renewal in our country.