Urban parks and the accessibility to them are considered as the most important factors in evaluation of urban performance. Suitable accessibility to parks is depended on the spatial distribution of them in the urban accessibility network. In the most studies that have been done about assessing the spatial distribution of urban parks, simple buffering method which has a high level of errors is used to determine the service area. Considering these problems and concepts existed in graph theory, network analysis can be usefully utilized to assessing the spatial distribution of urban parks. Network analysis provides a useful instrument for assessing the distribution of urban parks. In this study, using accessibility network of Tehran city and defining the location of parks on it, the service area of each park was determined by network analysis. Serviceability indices-i.e. service area ratio, service population ratio and statistical indices-i.e. park area per capita, park area ratio were evaluated and the situation of the city regions were compared. Based on the results founded in this study, 43 percent of the residual areas in the study area are placed out of the urban park serviceability. The map of these areas was prepared to use in locating and introducing new urban parks.