A particular system of urban parks should have its own locational efficiency, which is determined by the geographical locations and sizes of the individual parks within it. This paper suggests a methodological procedure for measuring the locational efficiency of urban park systems, within a spatial interaction model framework, and demonstrates its practical efficacy by implementing the procedure with the empirical data collected from the city of Chongju, South Korea. The results of the research show that the existing four-park system is less efficient than the seven-park system the city of Chongju plans to construct in the future. In the case of the seven-park system, more space should be transferred from the eastern park site to the western park area in order to establish a park system with higher locational efficiency.