【Objective】 This paper aims to evaluate the suitability of park construction quantitatively in built-up areas of small and medium-sized cities, to optimize the layout of urban park green spaces according to the distribution of suitability, and to preselect a group of parks for construction. 【Method】 Gaoyou City was chosen as a case study. Based on GIS technology, we synthetically considered the ecological service and social service functions, and analyzed six major factors that affected the location of urban parks, that are, suitability evaluation of the park construction land, urban heat island effect rating, air pollution rating, park accessibility assessment, evaluation of urban disaster prevention and hedging service radius, and population distribution. Delphi and analytic hierarchy processes (AHP) were used to determine the weightings of six factors, and the suitability of park location was then evaluated according to the overlay analysis of the different weights.【Result】 The site was selected to be located in an area that was suitable for construction. Through the location allocation (LA) model, a large park and seven small parks were selected as the keys to construction projects in the near future. 【Conclusion】 The method of quantitative data-aided qualitative analysis made up for the shortcomings of the traditional methods, which lacked science and accuracy, and can therefore provide a scientific reference for the construction of park cities.