Park green space is the most important part of the green infrastructures and the rationality of its spatial distri-bution determines the service's quality and level that it can provide for citizens. Using the network analysis based on GIS technique,we evaluate the accessibility of park green space in Nanjing from three vehicles include walking,cycling and driving. The service effect of park green space is not good in Nanjing and its accessibility in downtown is better than in suburbs,the accessibility is reducing from the center to the edge of the city. As the travel speed increases,park green space's service areas of central city are larger in less travel time and smaller in more travel time,while park green space's service areas of suburbs are lager in any travel time but not obvious. The distribution of streets with good fairness is dispersed,and streets with poor fairness are located in the suburb and a few streets are located in the central district.