Green roof policies has helped to advance urban greening by creating green spaces on previously unused rooftops. However, there are no requirements covering matters such as greening methods, operation and maintenance obligations and many problems for sustainability and functioning of green roof and green space have been pointed out. This research is intended to clarify the contents and criteria of green roof policies currently implemented in Korea, Japan and other countries, compare them with the evaluation criteria for sustainable and public benefit rating systems and propose comprehensive indices for evaluating the multidimensional functions of green roof from the perspective of urban open space. As a result, it is found that obligation, grant, reimbursement, density bonus and tax credit are frequently used as green roof policies and 41 criteria including percentage of greening area, percentage of trees or shrubs, reduction of heat island effect, open space, landscape, and promotion of biodiversity are identified as criteria applicable to evaluating the multidimensional functions of green roof from the perspective of urban open space, respectively.