Urban green space is one of the main carriers of sponge city construction. Compared with urban square land, urban subsidiary green space, and urban protective green space in urban green space, urban park green space has a higher potential for storm and flood control. However, due to the current urban green space, the lack of consideration of site selection and time sequence construction for sponge construction during the transformation and construction of the sponges in parks and green spaces has resulted in the failure of effective use of the rain and flood management and control capabilities of urban parks and green spaces. In order to give full play to the rain and flood management and control capabilities of urban parks and green spaces, the study constructed an urban park green space sponge suitability evaluation system based on the Delphi method and analytic hierarchy process. The results of urban park green space sponge suitability evaluation results were proposed and the regional level urban park green space optimization was proposed strategy. The SWMM (storm water management model) model is used to conduct scenario simulation and compare different scenario data. It is found that compared with the current system simulation results of urban parks and green spaces, the total runoff volume after optimization of the suitable sponge construction area is reduced by about 5.12%, and the peak runoff volume is reduced about 19.605%; After the optimization of the more suitable sponge construction area, the total runoff is reduced by about 19.02%, and the peak runoff is reduced by about 23.645%. The simulation data shows that the sponge optimization strategy at the regional level can effectively improve the rain and flood management and control capabilities of urban parks and green spaces. Based on the sponge optimization strategy at the regional level, this paper proposes a site-level urban park green space sponge optimization guide construction strategy. The suitability evaluation and optimization process of urban park green space sponges is expected to guide the optimization of different types of urban green space sponges in the future.