A method of accurately evaluating the spatial equity of urban park green space oriented by the theory of green space equity and helped with geographic information system (GIS) was proposed by optimizing the accessibility evaluation model starting from service capability of urban park green space and human demands and using indicators including effective green space service capacity,multi- threshold green space service coverage,accessibility,and location entropy of green space service per capita to improve the use efficiency of the urban park green spaces and find shortcomings in the distribution/layout of park green spaces. A case study of Haidian District in Beijing was conducted as an empirical study for spatial equity of urban park green space in Haidian District. The results showed that the supply of large-scale urban parks in Haidian District was sufficient. The supply of community -based recreational green space in Haidian District needs to be improved. Royal Mountains and Gardens of Beijing Western Suburbs construction greatly improved the accessibility of community green space. Based on the results,it is recommended to increase the green area of community-level urban parks and increase the convenience of community access to green space. It is indicated that the method of accurately evaluating the spatial equity of urban park green space proposed can provide a basis for the renewal and planning decisions of urban park green space.