Under the background of “urban renewal”, the research on the accessibility of community park space is of great significance for optimizing the supply and demand matching of community parks and promoting the construction of high-quality community living circles. In view of the shortcomings of the traditional spatial accessibility measurement method in identifying the supply and demand relationship is not accurate enough, optimal supply-demand accessibility method is introduced. Taking Gusu District of Suzhou City as the empirical area, the optimal service configuration of community parks and residents is explored. According to the configuration results, the time required for residents in each residential area to obtain services and the coverage rate of community park services are determined. (1) OSD can objectively present the actual situation of supply and demand matching in community parks by optimizing the allocation of service supply and demand. It is more accurate in identifying service blind spots and the physical meaning of the obtained accessibility indicators is clear. (2) The optimal supply and demand allocation results show that the overall accessibility level of community parks in Gusu District is relatively low, and the spatial distribution of accessibility is relatively balanced. High values are concentrated in the central and southern regions, while low values are clustered in the central region. (3) In areas with low spatial accessibility, targeted measures such as adding community parks, micro green spaces and vertical greening can be taken to increase service supply, and improve road network structure, to optimize accessibility levels. The research results provided scientific basis for the layout planning or adjustment of community parks, and provided reference for the study of park green space accessibility.