Bioretention facilities are one of the effective measures for rainwater management with low impact development. In order to explore the method of optimizing the configuration and parameters of biological facilities by using mathematical models, the RECARGA model was used to evaluate the hydrological regulation effect of the changes of design parameters and structure of biological detention facilities, and to quantitatively analyze the relationship between design parameters and hydrological performance, so as to determine the appropriate method of setting biological detention pools. The results showed that the soil hydraulic conductivity at the bottom of the facility was a limiting factor for the hydrological performance of the whole system, and the annual rainfall retention increased with the increase of soil hydraulic conductivity in a significant logarithmic function. There was a significant logarithmic function relationship between rainfall retention rate and facility surface area ratio. Rainwater retention had a significant power function relationship with depression zone thickness, and a good linear relationship with root layer and storage layer thickness. Considering drainage time factors, the depth of depression zone should not be greater than 15 cm. These research results could provide a theoretical basis for the scientific design of bioretention facilities structure.