As an important subset of the urban population and a major contributor to urban social wealth, the elderly play an important role in a city’s sustainable development. Based on data from the statistical yearbook and an empirical investigation, this paper evaluated the elderly suitability of 75 parks in China’s Shanghai Central District using a self-defined Python script tool based on ArcGIS. According to spatial differences in the elderly suitability of parks, we employed spatial interpolation to explore the reasons for variations in park services in different residential spaces in Shanghai Central District. The results revealed the following: (1) the elderly suitability of parks in Shanghai Central District decreases gradually from the inner ring to the outer ring; (2) the park accessibility in Shanghai Central District is generally low, and the park service space can be divided into five categories ranging from “low accessibility, super-low elderly suitability” to “high accessibility, high elderly suitability”; and (3) the advantages of regional function and location, the development of regional culture and tourism economy, and the implementation of regional elderly-care policies are factors promoting the improvement of the elderly suitability of regional park services. Finally, this paper provided scientific decision-making suggestions for Shanghai and other aging cities to optimize the elderly suitability of urban parks.